Firstly, I see a lot of people trying to compare apples to oranges with this game. Shadowrun is aimed squarely at providing a multiplayer experience, so comparisons to solo campaigns from other shooters are meaningless. Having said that, the training levels are enjoyable and the bot matches are fun and as challenging as you want them to be (great for trying out a new build or getting to grips with another race).
The format of the games is similar to counterstrike: two teams compete in a best-of-eleven-rounds matchin one of three game types: extraction (a normal CTF type affair), attrition (kill the other team) and raid (one side defends the 'flag' and the other side has to steal it). Like CS, if you die you're dead for the round, although you can be resurrected by a teammate (it's not quite as simple as it sounds; you could literally write a review about the intricacies of Shadowrun's rezzing system). Between rounds you get to spend the money you earned on weapons, magic or technology (I'd recommend going for magic and tech first, as you don't lose those when you die).
Gameplay is a blast, I've never seen teamwork as evident in an fps before. If you aren't such a hot shot, you can make yourself useful by healing and rezzing allies, or putting down magic traps to frustrate your enemies. FASA have introduced a whole host of new tactical elements to FPS gaming. My online experiences have been very good so far, and I've not experienced any abuse, other than mild annoyance when somebody accidentally kills their own side and once when a player repeatedly started votes to kick whatever player killed him in the previous round (SR has an option to kick the player who starts the votes, so he was soon kicked himself!). Generally people are positive and the elitism and trash talking that was so common in Halo 2 doesn't seem to be around (yet).
There are issues getting into games and it usually takes me about 5 minutes to find a party, which is longer than it should take but it's not that bad either. Once you've joined a group, you can usually stay with them for as many matches as you like. I say usually because the game assigns the player with the best connection as the 'server' and if that player quits (you have know way of knowing who the server is) your match is terminated. More often than not the same players will immediately be moved to a new map and start a new match, but sometimes you get booted out altogether. FASA are aware of all of these issues and a patch is anticipated in the near future.
In summary, this is possibly the finest multiplayer FPS experience I've ever had and once some glitches are fixed and a bit more content is released (personally I think the number of maps is fine, but apparently there are some more that weren't ready for the retail release that will be available for download) I think this will become a classic in its own right. The pricing point is perhaps an issue and I must confess that I paid less for my copy than Play is selling it for (and it is a brand new copy). If you're unsure then I'd recommend downloading the demo, completing the training and having a few matches against the bots. I was sold within minutes of playing it.