Feeeebbbdbdbback!
Pros-
1) Really interesting geometry. One of the things that has been true of a lot of modern TF2 levels is a reliance on outdoor environments. Other than gorge, roughly 70% of any given level is in an external combat space. Asteroid has, by comparison, 70% (if not more) of the level indoors, and what is indoors looks awesome. There are all sorts of interesting paths and routes to get inside, which makes the map fun to play, and helps alleviate some of the problems associated with CTF maps (which have a similar sort of fortress structure) with a game mode that spreads itself all over the base, as opposed to an absolute focus on the intel.
2) Space theme looks like its shaping up to be amazing. This is tied in with the first point, but it should be said that a lot of really interesting ideas seem to brew the crazier the TF2 theme goes. Farms are pretty boring, lots of really solid 90 degree structures with pragmatics, but a space fortress on a floating asteroid? Neat!
3) Layouts (as they are currently set up) are pretty intuitive, compared with the original layout with the teleporter.
Cons-
1) Game mode is very binary in terms of progression. I've played the map several times where a team would secure 100 to 200 points quite quickly, and then the game would grind to a halt as the sentry farms started to develop. I've played matches where the score line was 15-15 for ten+ minutes, with neither team really being able to secure any additional points. I've also seen a single core grab create such a ridiculous deficit that the other team could never come back from it.
Basically, the game mode seems to have a real momentum problem: nothing seems to be able to push players into actually accumulating points. In a payload or a/d map, the defending team wins if the offenders do nothing; the game mode naturally resolves itself if the players are incapable of breaking a stalemate. In a 5cp map, if you complete a round and earn a point, you are in an advantageous position, because it means that if both teams turn into goldfish (leave there computers, afk, die in their seats) the game mode still completes. The team with the highest rounds won wins when time runs out. This means that there is a significant incentive to win rounds, instead of sitting around and waiting for an opportune moment. Obviously the team that is ahead does have some incentive not to push in (they'll win by being ahead) but the other team then has a priority to push in, and vice versa once that teams wins some rounds. ]
The point is, I don't like game modes that allow players to do nothing for extremely long periods of time without some sort of punishment or positive incentive to push out. RD, as it is currently set up, gives players just that opportunity. You can sit in your base for forever, build up a ridiculous defense and it will take the attackers a really long time to actually score even a slight amount of points (the robots at the front give like nothing, and the secondary ones dont' give much either).
2) I hate shooting robots. I mean, MVM is fine, those bots at least move around, shoot at you, pop ubers, etc. These little objective bots are really annoying, and I dont like them. First, they are not particularly hard to shoot, they don't move or dodge when you're firing at them, but you do have to stare straight at them if you want to land any shots. What this means, is that while you are accomplishing your objectives an enemy player has a chance to sneak up on you and get the drop on you. No other game mode has this issue; in a payload map you have to stand near the cart, but you can look around and shoot at anyone who comes close, in a CP map you can move anywhere in the capture zone, peak any place that's visible and predict enemy movements. In RD you can't, you have to stare pretty much right at the bot as you shoot it, and anyone can sneak up on you from your peripheral vision and take advantage of you accomplishing your objective. Not fun! You shouldn't be punished by the enemy team for doing what you should be doing, just because they can look around and you can't.
But, even if we ignore that, the way that the different classes deal damage to the bots are annoying as well. Pyro and heavy have a real easy time shooting the bots, they deal continuous damage at close range (where you have to be to collect the resource anyway) and they do so in a way where if someone does attack them they can switch targets very quickly. Scouts, soldiers, demomen and pretty much everybody else have a really hard time actually accomplishing the objective in the face of enemies in the area. Any other game mode, with the exception of scouts getting additional capture, all of the classes are perfectly capable of actually accomplishing the objective. To me this seems like a real weakness. I don't feel like I should be punished for choosing a class that has flexible combat movement and limited ammo, when it comes to actually accomplishing the objective. I shouldn't have to choose a specific class when capturing a point, pushing a cart, why should I have to do so when shooting a robot? A class that reloads can just as easily capture a point, push a cart, capture intel, etc.
In some sense, I really just want more of a capture point mechanic. If I stand in a given area, I just naturally score points for my team. If an enemy player moves into the capture zone, I'm blocked until I take care of them. My ammo and weaponry is reserved for players I'm fighting, not for the objective I'm trying to accomplish! Standing in a given area should be enough.
I know that's not very exciting from a "wwooooooo coollllll robots!" point of view, but I've always thought flashy shit like that is annoying to play with anyway. Give me simple, easy to understand objectives that don't require me bending over backward to accomplish.
3) The core seems annoying to capture because of all the work you have to do to get it out. Vents are annoying, the one way door is annoying, the lasers are really tiresome (i've died so many times because its impossible to wait for them to lift while strafing, something you do compulsively as a scout to make sure you're ready to move when its time). It feels like the degree to which the enemy team has to be sleeping for you to accumulate enough points is already so high, that you don't need a ton of additional hoops to jump through to get out with the core.
The vent shouldn't be so long, and it shouldn't have pipes that force me to crouch when I enter. Its a tight narrow corridor that I can't dodge in, if the enemy team comes for me I'm dead anyway, I shouldn't be put into a huge disadvantage at the same time.
Lasers should be wider apart (not by much, just enough for modest strafing while you wait for them to drop).
one way door can stay, so its easy to get in. But its pretty frustrating that it exists. Its one of those things where I'm sure a lot of players are pretty flummoxed when they come back and the door doesn't work.