If you wish to play your rogue, go for it. But at 90; this is what i have experienced...
PvE: We are great but sadly i HATE PvE
PvP: We went from a super power to your personal choice of, One trick pony ~or~ support class for others. Let me just explain this a little bit further since for some reason rogues still wish to hold the illusion were independent.
One trick pony: Normally a sub spec with 0-3 macro's where SD is popped and all possible damage bonuses are directed specifically at the opponent. After this 100%-0% kill in seconds, they will hide in stealth and wait for all CD's to now be useable again in a “rinse and repeat” fashion (these rogues are easily spotted out since they will say they still fight while waiting for the CD's to be back up, but this time really consist of waiting at the graveyard for a resurrection or coming out of stealth to hit someone about to die). You can find tons of macro's and tips/helpers for this if you look online under many spec helper sites. (this is most useful in an arena due to its... twin suicide style)
Support PvP: Help slow FC's in games such as WSG or to turn the tides of an already existing 1v1 battle taking place on the side of the road in such games as AB. One could also use this in a group VS group battle such as fighting for mid in EoS. Stealth back and lock up the healer or one of the casters. Although this is very helpful to the over-all goal of the team, it can feel very.... poor in play. (this is most useful in BG/RBG)
In conclusion, I would like to say this is all ~my personal opinion~ mixed with ~what I have observed.~ If anyone had a break-through that goes against this post, please inform me.