Legionaire - A good class, often played well, players who play this class are often helpful and are team based. Viable on Perilous but had strain occurs because weapons take a long time to kill stuff.
Katari - Like all two handed classes in BioWare games, overall very shi**y. Weapon and ability damage does not make up for lack of shield and defense. Good times such as rings are a necessity. Crappy for perilous, you don't see them often and when you do they are on their face.
Assassin - Good class but played badly at higher levels at times. Fun class to play and cleans up on up to threatening. Can do well in small spawns if you have a good group, gets smacked hard on bigger spawns especially if the person is too aggressive.
Archer - Good class and fun, if played intelligently very viable on perilous, good choice of top notch weapons.
Elementalist - Very good class but off set by being perhaps the most annoying class. Wall of fire and firestorm are excellent abilities but are akin to flamers in ME3MP, the melee guys can't see shi*. Ele's that have and use barrier are loved by team mates and the class is viable on perilous even if the annoying skills are skipped.
Keeper - Excellent class all around. Excellent support and yet very useful offensively especially if using static cage. just about every one is happy to have a keeper in their group and most play a smart game.
Alchemist - Excellent class, one of the most fun to play. Viable on perilous but like the assassin you can't get away with things you could on threatening. Has really good crowd control abilities, even larger spawns.
Necromancer - Excellent class, fun to play and helpful to team mates. Viable on perilous, has an added bonus in that it's two initial abilities can carry you a long way and are good crowd controllers. Fearing and freezing enemies before the fighters get in close really helps. Some of their higher level abilities imo are a bit overrated however.
Reaver - Garbage class like the Katari. Fun enough to play on the lower levels but class design is similar to the lousy design of Korgans in ME3MP, you are weak, your weapons are only okay so we will make you main abilities give up health to get that awesome damage. Reavers end up on their face a lot.
Templar - Good class, much like the Legionnaire quite often played well. They have a few really great abilities and are viable on Perilous for sure.
Hunter - See the archer, yeah yeah...but they are oh so different, not really.
Arcane Warrior - Over played class, well played about half the time. A rare treat if they actually use pull of the abyss. Can carry whole teams on perilous, the unfortunate aspect is that they cannot afford to raise anyone at all it seems. More non team dirtba.....i mean players, play this class than any other by a wide margin.
My words are the LAW! This thread can now be close as their are not viable counter points to my unassailable logical post.