Cat trinket?

[:1]Tried to look up comparisons in the sticky here and at EJ and couldn't find a straight answer.

Currently, I've got Tia's Grace and Quicksilver Alchemist Stone. I now have enough TB marks to buy the Unsolvable Riddle. I am not sure which trinket to replace, if any.

Tia's Grace is overpowered and really should be epic imo. 285 Mastery and 340 Agi constant base stats.

Alch Stone, reforged Mastery, is 351 Agi, 117 crit, 77 Mastery base stats.

Unsolvable Riddle is 321 Mastery with a 1605 Agi / 2 min cd use, which if I did my math right averages to 267.5 Agi, BUT since it's a controllable Agi proc you can line it up with cooldowns and dots with a huge Agi boost to increase its value.

I am leaning towards Tia's Grace + Unsolvable Riddle here because the combo offers the most Mastery and not really at a sacrifice of too much Agi (if I use the Unsolvable Riddle's Agi proc appropriately).

Please let me know if I'm completely off. Thank you!
Try http://fluiddruid.net/2011/02/trinkets-few-more-4-0-6-updates/
You shouldn't drop Tia's Grace 'till you get Fluid death, and for your second trinket try and get an Unheeded Warning off from some BoT trash group (I didn't like the idea so i just bought mine when i turned 85).

OP: I never liked the idea of 'on use' very much for my trinkets, it only adds more unnecesary complexity to our rotation (which is still one of the hardest) and if you happen to forget using it you loose dps overall (of course you can macro it to something, but there goes the 'on situation' use)
Just bind it to Tiger's Fury and you should be good.
It's still pretty weak compared to other available trinkets though.
Thanks guys, I ask because I'm not sure when I'll be able to get those good trinkets. Definitely holding on to Tia's but I'm kinda iffy about which of the other two is better. It does seem kinda hard to line the trinket up with Rip, cause I don't always get to TF both dots either and missing the optimal use really devalues the trinket. Then again, the trinket isn't like TF in that you don't need it to get energy back, so you could wait to use it whenever you're going to be putting up Rip + Rake... idk.

I'll be looking out for the BoE but I'm not rich and my guild group won't let me roll because I heal for them.

[EDIT]: Ty for the list Tangedyn, Alch Trinket and TB trinket are next to each other on the list. I guess I'll stick with Alch Trink then, it's less complex / prone to error and if someone already did the math on the other trinket for ideal situations, then I won't argue.
Keep the alchemist stone and tia's grace. Don't buy riddle since the resistance trinket is much more useful (Nefarian and any resistance situational use) and has a longer lifetime. Unheeded warning is fairly cheap at 8-10k usually ,but probably less depending on realm.