Nuclear Dawn is one of the best mash ups of FPS and RST currently available on Steam. It is my impression that the only contender in thei genre on steam is Natural Selection 2, so i will do a little compare/contrast at the end of this.
-Excelent RTS gameplay. UI is basic, and at times a little clunky, but in general it gets the job done for both macro and micro management of building, upgrades, and resources. The biggest problem is relying on your soldiers to defend your structures and get you resources.
-Decent FPS class based combat. Each class has thier strengths, and thier weaknesses. Weapons are well balanced across classes and teams. Certian mechanics can be difficult if you are used to more FPS centric games, and getting used to having to rely on someone to get you better weapons and spawn points can be tough, but in gerneral the FPS gameplay is rewarding.
-A Great community. The people who play this game LOVE it. They set up events on popular severs, help out new people, and are very communicative.
-Small base of players. Time has taken its toll on the number of active players. At peak times there is often a server of 30 players or so, but other than that there are very few people playing.
-Small selection of maps. Although the community has done thier best to make a wider selection of maps, there are still a very limited amount compared to FPS centeric and RTS centeric games.
***Natural Selection 2 vs. Nuclear Dawn***
Natural Selection 2 has 2 radically different sides. Although this creates some more variety, thier strengths are appearant at different points throughout a match, which makes the game much more difficult to balance. At this point in time I would say that for balancing reasons alone Nuclear Dawn is the better game.
Nuclear Dawn has considerably larger maps than Natural Selection 2. This allows for more strategy for each commander, expecially when compared to Natural Selection's closed corridors and small rooms.
Both games have equivilent FPS gameplay, with the exception that NS2 is only class based for one of the teams. The other team can custimize thier loadouts (shotguns midgame, grenade launchers/flamethrowers late game, exo suits end game), but thier overall stats are the same.
Nuclear Dawn blows the pants off NS2 when it comes to RTS UI. Because the 2 sides have very similar buildings, the developers were able to keep the key bindings for each side's buildings the same, so it is very easy to play as commander for either side. This is not the case for NS2.
Overall, if you like FPS, or RTS this game is worth a try. Make sure to sign up with the community groups so you know when everyone else is playing.
A final note: This game, like many team based FPS, really requires a mic. You can still be an effective team member if you don't (there are in-game voice commands), but I can assure you that at least once every game you will wish you had it to call out enemy locations accuratly, or request supplies in a very specivic spot. For the RTS element a mic is a must.