Well, I finally decided and bought it last night for my Surface RT. It looks great on the bigger screen and runs smoothly (except for one time where it completely crashed my Surface, which then wouldn't reboot for several minutes...that was scary but it eventually came around), but there are a couple of things that irk me:
1. Achievmeents: If you get an achievement the classic green banner and noise notification don't pop up (this is like my favorite sound in the world and all other Xbox LIVE games I know have it, so it's disappointing this one doesn't).
2. The microtransactions: I hate games with microtransactions, requiring you to spend additional real money to buy the cool things like weapons and armor upgrades (I get why developers do this for 'freemium' games, but to do it in a $7 game is not cool). Additionally, I've heard from other reviewers that the weapons and armor you buy are only temporary! Is this true? You pay real money to use a weapon for one mission and it doesn't carry over? Who the heck came up with that? Regardless, having all the extra money on my $25 Microsoft card for the 928 promotion (in addition to the extra credits I can get via Bing Rewards), I'd rather have bought it on my phone to use to buy these upgraded weapons.
3. The controls (overall): Overall, the controls work very well. The developers did a good job of adopting the "Rocket Riot" control scheme of allowing your thumbs to migrate along the screen but continue to work (instead of say, doing it like Sonic the Hedgehog 4 or NBA Jam and having a tiny little virtual stick that you always slide away from forcing you to readjust), with the left side of the screen controlling movement and the right side controlling aiming. However, for the same reason I prefer Rocket Riot on my phone vs. Rocket Riot 3D on my Surface, I guess my hands are a little too small for the 10.6" screen and I find it a little cumbersome to hold the tablet while also navigating the controls (particularly switching to other buttons such as changing weapons or grenades). I think a smaller screen would've worked better for me here.
4. The controls (grenades):: Finally, while the controls are generally good, they really screwed up with their controls for the grenades. It is not intuitive at all. Instead of letting you switch to grenades and tap the screen where you want to aim it, it simply launches the grenade in the direction the character is facing. Even if you take the time to face your character at the intended target, more likely than not you'll still miss the target, thereby wasting the grenade.