I've put about 5 hours in by now, half way through the Rank B missions.
If I had to give it a score, I'd probably put it at 7/10. I have a few issues, but none of them are really anything that completely ruins the experience.
First and foremost, which has been mentioned before, is the font used. It's terrible, makes the reading a bit awkward. Why this wasn't caught and changed boggles my mind.
The UI for managing your Dock, to change the parts, is a little bit clunky. Combined with being unable to change the X to Accept and the O to cancel has caused me to sell a part I didn't mean to sell more than once. It's hard to break that habit to press X, I guess.
Mission variety has been okay to decent, so far. A couple escort style missions, a few delivery / fetch missions. Most are just destroy X amount of enemies, or destroy a specific enemy. Weapon variety has been okay, I would have liked the UI to be a bit clearer on what type of weapons did what. Its fine once you know the symbols, but its a bit confusing at first. The manual is no help, as its basically 4-5 pages.
I think I would have liked a slightly higher point of entry and had the DLC rolled into the main game for release. So far there's been less than 15 missions per rank, and it would have been nice to have more missions without forking out more money for the DLC.
Overall, I'd still have to say its actual game play is similar to the Strike games from the PSX days, with the parts + mech customization of Front Mission / Armored Core.
Really good for what it strives to do, definitely worth the $15 price of entrance even with my nitpicks.