So what's its uses? What can it do? And what's its limitations?

Its uses are few and far between TBH,

* March Blocking
* Lone Character/WM hunting
* Pursuing
* Trap making

March Blocking

Obviously it's the most used way with the gyro, it's huge 20" move means it'll be behind units quickly. Staying right close gives it the ability to stop units marching and thus giving your artillery more time to knock off ranks for combat, also the gyro can help here; the steam cannon stands a chance of knocking a few down. The enemy have to decide a few things - Turn and fight it, thus wasting a turn or ignore it and how the shooting/magic can down it. If they turn that's a turn wasted and the gyro can just fly over and past them, if they ignore it they're crawling towards your blasting artillery.

The downside being its vunerable. T5 W3 and a 4+ SV isn't much, a round of shooting with maybe two units firing at it could down it in a turn. It also has to be concerned about WMs, most allow no save and a single hit could spell it's end; thought it's crash could kill more than it was alive.. ^_^ Also fear magic or other flyiers.

Lone character/WM hunting

Another very good use for it. The steam template is most likely to cover WM crew and should easily get lone heros, the down side is that anything with good save or more than one wound is basically safe. This use of the gyro is guranteed to buy you more time and annoy the hell out of your opponent, and with the 20" you can be there in a turn or two; as well as get out of his LOS in a turn if need be.

Disadvantages are that it's not march blocking and its easy to take down. A single round of concentrated fire could down it quickly and effectively, not much use if it's a hunk of useless metal.

Pursuing

Another good use of the gyro, due to the dwarven stunted legs we can pursue a lot less effectively than other races. This is where the gyro comes in, two ways of doing it really; {A} You charge the gyro in when you think you're going to win (or as good as won): this gives you a good chance of breaking and catching them (3d6" pursue) or {B} Charge a fleeing unit with the gyro, if they don't clear the 20" charge (not all that likely) you will destory them.

Trap Making

Simple, the Gyro is a nice and relativly easy 100+ VPs. So a nice bit of baiting and you could draw units into a careful trap, also it has nice uses against frenzied units. The idea is quite simple really, you should need no idea of how to get this working.


So in general is the Gyro worth the points? I'd say yes and no, in certain armies its definatly worth it; whether it gives you that extra round of shooting or a turn of advancing without enemy fire it can be invaluable. The uses are of it simple and effective, but so are the ways to down it. All I can say is becareful, march blocking is all and well but you will be very exposed.

KU

(*Disclaimer - I have no real experience with the gyro, these comments are derived from other people's words and my small use of the gyro.*)

One thing you haven't mentioned, and the use that I tended to find it most useful for, is that it completely devastates T3 units, which happens to include the units most Dwarfen armies have trouble with - fast cav and skirmishers. A flank shot on a unit of fast cav can easily remove them from being a threat to anything in your force, without risking the gyro at all. Shooting at skirmishers is more of a risk, but it can pay off nicely, especially since they won't be able to claim a rank bonus against you if they decide to charge it.

Likewise, against T3 armies, like Goblins or Elves, the gyro can be ridiculously good. Killing 5 or 6 elves with a single burst from the steam gun feels really good, nevermind the attention the elf player is likely to give to this unit that's mostly irrelevent to your overall plan.

Obviously, if you're playing against Chaos, you're going to regret taking something that can't do any serious damage - it still has a role, mostly as a march blocker or a suicide rush hoping to scatter well on the explosion, but that's not where it's best.

Overall though, I'd say that the gyro is a really important unit in the army tactically, and it's one that I'll very rarely leave at home, especially if I'm playing light on shooting; any chance to control your opponent's movement and choices are a huge benefit, especially in an army that can't redeploy fast enough to react effectively to surprises.

I think the Gyro is great, for the purposes you mentioned. In a Dwarven army, something that moves 20" and can thus go WM hunting, march blocking, pursuing and baiting is especially important, because no other part of the army can do these things (except Miners, maybe).
Its the same reason why Carrions are so important in a Tomb King Army. The whole army cant march and is thus rather slow, making a flying unit very valuble. In a Dwarven army, the Gyro is even more important than carrions for TK, because with TK at least its possible to move double speed by getting an incantation going in the magic phase, to pursue 3D6 with chariots and cav and to go WM hunting with scorpions and swarms. All these things the Dwarves have serious problems with or cant do them at all, respectively.

With T5 and a 4+ AS the Gyro is rather safe, at least we can be sure that arrows and S3 spells wont be harming it much. If we compare it to Elven Giant Eagles, it is of similar durability as two of them. Eagles also have 3 wounds each, but with T4 and no AS they are shot down rather quickly, or at least have to take a panic test.

Its steam cannon makes it even better. What Vrish said about its causing damage to T3 units is true - especially against valuble troops, e.g. High Elf Ellyrian Reavers, it is great, as each wound it causes will make a big difference.


The downside is obviously that it is a rare choice. Otherwise it would be too good though. High Elf Eagles are also rare (for two), and, as said, two of them are of similar quality as a Gyro.
It might seem ashame to use up a rare slot - unlike Elves Dwarves are much more dependant on their warmachines, that the rare slots could be used for - but on the other hand, they can get warmachines as special choices too.


All in all, I think the Gyro is a great addition (especially) to a Dwarven army.