The battlesuit. Is there any more iconic unit for the Tau Empire? And of course, the reason it's so iconic is that, in the first and second codexes, it's had to do almost all the heavy lifting for the army, in terms of fielding special weapons. Oh sure, you could put a single fusion blaster on a Piranha, or a twin-linked plasma rifle on a Broadside, but if you needed anti-light vehicle or -heavy infantry firepower, the battlesuit was your choice.
Plus ca change, as the French say.
But first, the humble stealth suit. Sadly, the stealth team is at something of a loss, yet again. Their points cost hasn't decreased, though the change to burst cannons does mean each suit now has one extra shot. Their stealth generators still provide them with Stealth and Shrouded, giving them a 4+ cover save in open ground, and making them almost terminator-tough in area terrain (T3 vs. T4). They even have multitrackers and blacksun filters built into their suits now, though it's hard to imagine why, since the suits only have one weapon and it would only offer a whopping +1 to a cover save before running out of range. Plus, they have Infiltrate, so with a 6" move that isn't slowed by terrain they really shouldn't have any trouble getting close enough to ignore Night Fight all on their lonesome. They can take a choice from the support systems list, but there's really nothing there that provides much; perhaps the Advanced Targeting System, given their shot output, or the Counterfire Defence System, given how close they have to get to actually open fire. You can upgrade a squad leader, who continues the silly trend of Tau squad leaders getting an additional A rather than something useful like a boost to BS or I, and the squad leader can take some drones, or a homing beacon, or a markerlight and target lock. And they can all take the bonding knife ritual, at one point per model.
It's not that the stealth team is bad, exactly. 3+/4++ cover save (minimum), with four S5 shots, and jet packs, isn't a bad deal for 30 points. It's just that, yet again, the stealth team doesn't bring anything different. It's the same S5/AP5 firepower that the basic trooper is toting, and while that's great for Fire Warriors, it's underwhelming in a contestant from the Elites slot. Although at least now they have a better shot-per-point value than Fire Warriors. They can get a single fusion blaster for every 90 points worth of suits, up to a maximum of two whole fusion blasters. And that's it. They're excellent anti-infantry, but Tau don't suffer from a lack of that, and as T3/W1 models they're not that hard to get rid of, even with their impressive cover save. You won't get laughed out of the room for taking them by any stretch of the imagination, but they continue not to really measure up to their competitors.
Especially since, unlike the stealth suit, the XV8 Crisis suit actually did get a points break. For three points less than the last codex, you get a suit with the multitracker and blacksun filter already built in, effectively saving ten points and, more importantly, freeing up the by-default multitracker slot for something different. Crisis teams have almost no options as a unit; someone can upgrade to a squad leader, they can all get drones and the bonding ritual, the squad leader can take signature systems (though it doesn't get another slot to put those in). But that's okay, because they have all the ranged weapon and support systems lists to choose from. And the choices have really expanded, thanks to several factors. The built-in multitracker allows flexibility and redundancy; combine Deathrains and Fireknives, for five points less than the old Fireknife! The clarification that suits can take multiple single weapons (found in the most recent FAQ) provides volume; rather than two twin-linked missile pods, take two single missile pods, and trade six twin-linked shots for twelve basic shots! And the new support systems offer a variety of tactical options. You can go for Interceptor, or Overwatch at BS2, or Precision Shot. It all changes the way your suits perform, and offers you a variety of options for using them on the field.
Like the Ethereal, XV8 squads have simply and undeniably gotten better. They can put out more firepower for less points, they have more options, there are more support systems worth considering, and with a Commander to provide either support or defence (or both) they can really chew up whatever you point them at. The only thing that stops them from being the same 3x3 auto-include they were last codex is their big, big brother.
The XV104 Riptide is awesome, and I use that in the classical sense; it inspires awe. For roughly the cost of an old, fully equipped Hammerhead, Tau now have access to a T6/W5/2+/5++ jet pack monstrous creature, toting around either an eight-shot S6 heavy burst cannon or a three-shot S7 AP2 ion accelerator, plus a twin-linked SMS, plasma rifle or fusion blaster. Considering how flimsy Tau units have historically been, to suddenly have not one, but two units in the army that can take a punch (or lascannon to the face) is almost too much to handle.
The Riptide also comes with a couple of neat little tricks. It can bring along up to two shielded missile drones, who likewise have T6 but trade 2+/5++ for 4+/4++, and add some additional firepower to the unit. Of course, those drones do count for break test purposes, and the Riptide is only LD9, so they're not always worth it. More useful by far, though more dangerous, is the Nova reactor. Activated in the beginning of the movement phase, it allows you to either upgrade the Riptide to 2+/3++, give it a 4D6" Thrust move, double-fire its secondary weapon or fire its primary weapon in its devastating NOVA charge mode. Of course, there's also that danger I mentioned. In order to use the Nova reactor, the Tau player has to roll a d6, and on a 1 or a 2 the Riptide not only can't use that upgrade that turn, but suffers a wound with no saves of any kind allowed (though FNP still works against it). It's not something to rely on every turn, but sometimes you really do need a S9 AP2 Ordinance large blast, or 12 rending S6 shots, or to double-fire your AP5 cover ignoring SMS at some approaching Orks or Tyranids.
And as if that weren't enough, all on its lonesome, the Riptide can also buy up to two options from the support systems list. For 190 points, you can basically forget about enemy units dropping in your face, unless they look forward to the idea of facing a S8 AP2 large blast (which, admittedly, Gets Hot) with Interceptor. And you've still got a slot left; want to give the 12-shot S6 rending weapon Precision Shot? Or either of them Skyfire? Or give the big guy FNP, just to make him extra-absurdly hard to kill? The options aren't exactly limitless, but they aren't small, either.
For games of any particular size, it's safe to assume that a Tau player who isn't running a themed no-suit list is going to be putting a Riptide and some fire-support suits down on the table. It's a change from the old 3 x XV8 squads, but not a particularly sharp one, and it's set to become just as standardized as the old setup ever was.
Of course, there's a reason for that. There's just not much point in doing it any other way.