I've played it before the major class skill tree rework and after it. It's good if you want some casual play. E.g. you want to spend 20 minutes and have lots of action while slashing and shooting hordes of enemies. On a medium difficulty mission you can face about 1,500 enemies, so it's really hordes. The characters in your team interact/talk with each other automatically, which creates immersion. Who interact with whom and in which way depends on character classes and their past, which you select when creating a character. You also have a voice chat. The skill tree rework didn't impact the gameplay too much, IMHO. Before the rework you had 5 times (on lvl 10, 15 etc. max lvl 30) when you can select one of 3 skills, total choice of 15, and you could change the selection at any time. After the rework you can still change the selection at any time, but now you've got long skill trees with branches and 30 skill points to spend. It gives you more choice and flexibility, and allowing you to max out a particular area (or build a balanced character if you want).
While this is Warhammer 40k setting, there are no Space Marines, you only have Astra Militarum: humans (sharpshooter, zealot, and psyker) and ogryns. You can specialize those into different playstyles via skill trees and selection of wargear (weapons). E.g. as a psyker you can cast "magic" and stay behind the team mates (since you are a "glass cannon") or you can get a sabre and a laspistol and be at the front and use no psyker skills if you build your character that way. As an ogryn you can also stay behind and shoot an e.g. grenade launcher, or build a bullgryn, grab a shield (armored bunker door) and a mace, and charge ahead.
The premium skins give you nothing, just aesthetics, plus you unlock some skins as you progress through the ranks.
The game had some bugs, when just released. For me in particular, it was a disconnect just after you join a battle. But this was fixed long ago.
For $26 it's not too bad. I think it was much more when not on special. So, if you like slash'em up games it's good fun.
