I will say the 0.5 my boyfriends sister had was silly. About 2 inches or so front to back! >< she could barely find a plant to fit - so now I have it,
and I use it... For transporting fishies and if I get a fish who comes home late with me they may sleep in it over night but then are transferred ASAP to a bigger tank.
I will say my java fern never complained about my tank size :p Gary plants are awesome.
As for being bashed for a 2.5 - here, ask away! You need help, come to this thread. I amongst a good number of others will do everything we can to help you out with what you have!