Things I like:
It keeps the unit types simple but interesting. I'm a fan of Advance War, especially the earlier GBA versions where they kept the unit types relatively simple. I think for this type of game that is preferable, where ever unit has a role to play rahter than ever-escalating weapons of increasingly mass destruction that make cheaper units redundant as is favoured in the RTS mould. Uniwar achieves simplicity with a smattering of variety to keep the different races interesting but not unbalanced.
Game lengths are perfect for a handheld game. Brevity is important on handhelds, you don't typically sit down for a 'gaming session' on your iPhone. You have a blast during an advert break or while you're cooking dinner or while you're on the toilet, short is sweet.
Healing stations seem redundant. Healing itself is something that I find myself rarely using as it wastes a turn and it's easier just to make new units. Healing stations I've never, ever used because to do so would invariably waste three or four turns for the unit in question, moving back to the station, healing and moving back to the front line again. During that time, I could have just replaced the unit with two of the same.
So far the campaign missions are a bit easy. The computer AI doesn't seem super smart and generally the most effective tactic seems to be churning out units. The computer AI also doesn't seem to use any of it's special abilities; several games now I've been watching out in case it used the bury or infect or plague abilities to turn the tide of my assault and it never has. There's been specific circumstances where had I been playing the computer AI, I would've buried under my front line and capped bases from behind. Generally, most games involve pushing the enemy back to their base, surrounding the bases so they can't churn out more units and then capping.
Generally, the campaign is so far playing like too much of a tutorial and not enough of an tough campaign.
I suspect these issues are because the game also has an online component. I have enjoyed what I've played so far.
There should be a patch in the coming [month?] or so that will address the AI issues though.