More will join this conversation as the Tau codex spreads, but I've got one in front of me and I feel like starting it now.
First, let's summarize the contenders:
In the bomb corner, the sunshark bomber. With 3 hull points and an 11/10/10 profile, this is not a terribly durable flyer. It comes with a networked markerlight, which means that it can boost its own BS and fire its own seeker missiles, in addition to laying down marker tokens for other units to exploit. The bomber's offensive arsenal is rounded out with the pulse bomb generator (5/5 Large Blast, and unlike any other bomb in the game, it reloads on a 2+) and a missile pod (36'' 7/4 Assault 2) (which can be cheaply upgraded to a twin-linked missile pod).
The bomber comes with a pair of passengers, jet pack infantry drones that can turbo-boost like jetbikes armed with twin-linked ion rifles (30'' 7/4 Rapid Fire or 8/4 Heavy 1, Gets Hot, Blast). Note that while they are embarked, the drones can fire as though they were passengers... passengers who still have the relentless special rule, which means that their guns may as well be mounted on the bomber as well.
In the strike fighter corner, the razorshark. The same fragile profile. Armed with a burst cannon (18'' 5/5 Assault 4) (can be traded, cheaply, for a missile pod) and a quad ion turret (30'' 7/4 Heavy 4 or 8/4 Heavy 1, Gets Hot, Large Blast). Also, for what it's worth, a pair of seeker missiles.
Both can take upgrades from the vehicle battle systems list. The only ones that are relevant are the automated repair (can remove immobilized and weapon destroyed results, but can't restore hull points), decoy launchers (4++ vs Interceptor weapons - basically an auto-include for flyers), and disruption pod (+1 to the cover save - also an auto-include to improve Dive! saves).
In my opinion, neither flyer is really a game changer on the level of, say, a stormraven or a doom scythe. Neither carries troops (though the bomber does have a pair of jet-boosting models that count as a denial unit...). However, I hesitate to dismiss either of them. They both field some tasty weaponry, and we all know by now that when it comes to flyers, durability is far less important than timing - and that decoy launchers upgrade can give a flyer a fighting chance.
Now, on to meat of the matter: which one is better? Obviously, we all want to magnetize the cr@p out of this kit, but it's still an interesting question.
Like I said, I won't dismiss either model. The fighter is pretty tasty. The burst cannon isn't too exciting - like their old codex, the new one provides a plethora of strength 5 shooting - but missile pods are never to be sneezed at, especially one on a flying platform. Strength 7 shots will pop many enemy flyers, and with 36'' range and a flyer's speed (and what looks like a 360° turret for that missile pod mount) the razor shark can easily engage almost any flying target on the board. That quad ion turret is also pretty nice. Four Strength 7 AP 4 shots will terrify GEQs and threaten MEQs. The large blast version doesn't pierce 3+ armor, but a Strength 8 Large Blast is still pretty exciting. I can see fielding the flyer.
However, I think the bomber is the clear winner.
The bomb itself isn't too exciting. Like I said, the Tau already have a huge amount of 5/5 shooting, and dropping a 5/5 bomb on a squad of MEQs isn't any more effective than, say, rapid-firing into it, though a flyer's ability to deliver that blast where you need it (say, on top of a squad of heavy weapons guys hiding in your opponent's backfield) is not to be ignored.
The "secondary" armaments, however, really impress me. A twin-linked missile pod? That's a scary weapon that will pop most other flyers and threaten almost any model on the board. The Tau have been using the XV8-mounted version of this weapon - the "deathwind configuration" for a long time, to great effect. The intercepter drones are also really exciting. Remember, they are relentless passengers that can fire while attached to the bomber. Their guns are basically mini quad ion turrets - which makes the razor-shark's main attraction all but obsolete - and they have the added utility of also being able to detach and contest objectives or generally harass the enemy. And they are fast little buggers. and let's not forget the utility of the markerlights. They either make the sunshark markerlight-independent - which lets you focus your markerlights on other targets - or let it act as a secondary source of marker tokens for the rest of your army. Wonderfully versatile.
Versatility is ultimately why I prefer the sunshark by a great deal. It kills flyers, it threatens infantry in the backfield, and it has the weaponry to hunt down vehicles as well. It comes with its own markerlights. It carries denial units with tasty guns. What's not to love?
But... what do you think? Agree? Disagree? Did I get a rule wrong? This is a forum - let's get foruming!