Hello.
Of recent I have been playing with and as a Lore-Master, and when playing with one, they are confused as to what pet they should have. So, here is a little thing to say what pets I think the persons should have in certain situations. This is merely my opinion, so please comment if you agree or disagree.
This is based on the LMs I have been playing with, mostly level 30+.

1, soloing. When soloing, any pet is good. A bear has most powerful auto-attacks, and highest defence, so it is good if you want to avoid getting stuck by the enemy, as you can make the bear force the enemy onto him. A lynx has Surprise attack, which is utterly brilliant for starting a fight, and will allow you to kill the enemy much much faster, however, the lynx is weakest of morale and auto-attacks, even weaker than the Raven. A raven has moderate auto-attack dmg, and moderate morale. It is no attacker, however. Unlike the bear and lynx (Or perhaps all other pets, I'm not sure) it doesn't have any actual attack, unless you count Distraction (has a weak light dmg DoT) as one. The good thing about the raven, however, is it can debuff the enemy, making it much easier to kill quickly. Raven is also a good choice for soloing against higher level foes, and foes with higher morale, as it has higher flanking chance than the bear or lynx. Lynx is greater than the bear at flanking.
2: duo. When playing a duo, best thing to do is note your ally. If he/she is a Captain, Champion, Guardian, or Warden, a Raven or Lynx would be the best choice. A Raven can debuff the enemy so the more DPS roles (Champion, overpowered Guardian, Recklass Warden) can kill quicker. Lynx is more DPS with surprise attack, so can, once again, kill the enemy more quickly. A bear wouldn't be too good choice, because it is more of a tank, and each of the classes above can pass as tanks. When fighting with a Burglar, Hunter, Minstrel, or Rune-Keeper, perhaps the best choice would be a bear. The bear can draw easy aggro, and none of these classes want aggro. Hunter, Minstrel and Rune-Keeper are strongest at range, so if bear can hold enemies off, and these classes can range the enemy, they'll be better. Burglar, meanwhile, required being behind the enemy, so could easily sneak up behind the enemy if it concerntrates on the bear. Burglar can also Prevoke the enemy while it fights the bear. If playing with another LM, any pet is good, but I do not recommend having 2 of the same pets, as 2 bears using forced attacks will be useless, raven debuffs won't stack, and when 1 Lynx enters combat, the other will come out of sneaking. A word of advice: when playing with another LM, Rune-Keeper, Hunter, or Warden, a raven is often good choice, because of the Fire-dmg debuff the raven has. With a hunter or warden using fire oils, you can deal a heck of a lot of damage.
3: Groups. In groups, best choice is probably Raven or Bear. When in groups, there is likely to be 3 class roles: healer, tank, and dps. A tank (aka Guardian, Champion, Warden) will force the enemy onto them, and will lead the change, so Lynx won't be able to use Surprise Attack, because when it enters combat (If another player enters combat, Lynx does as well), he can't sneak. Raven is best choice, because it can debuff the enemy, making them easier for the tank and dps to kill. Bear is also a good choice, because of Shattered Arms, which will make enemy much easier, and not only for the tactical classes. Bear is also a good choice, because it can easily protect a healer. Raven is good choice because it can flank much more often, thus you will not die so easily (Using Wizard's Fire on flanks).
This is my advice, and you can do as you please with it. I have done some Skirmishs where people use a bear while I am a warden, and Lynx while I am a Rune-Keeper, so thought I would make the effort to give my advice.
Good luck to you all. See you in-game.
Signed:
Count Azinbah Hambel Batlord.