Saint's Row still worth?

Well if you haven't played it much on your PS3 then why not? I enjoyed the game a lot more in co-op than solo though.

Get it. Fun game, you get Saints Row 2 as well, and $5 will get a lot more to boot, like all the DLCs.

Saints Row The Third is good and worth it ;)
Also, if you plan to play Saints Row 2 on PC too, prepare for a badly optimized port, so you will need to use a fix for a better experience, lower some effects and maybe use the "Gentlemen Of The Row" MODs. More info here: http://steamcommunity.com/app/9480/discussions/0/846958724811426425/

It will get Workshop support soon too ... totally worth it.

Did you enjoy what you played of it on your PS3? Do you want to play more of it? There's your answer. :)
If a game is enjoyable it's always "still" worth buying, being new doesn't make a game worth buying.

SR3 will be always worth.