LTA and BTA... same tank??

[doch]

Long story short, I tend to impulse buy. I have an LTA that just went in my tank a week ago, and then I came across an amazing purple BTA... so I put it on hold so the LFS could make sure that it's healthy before I take it home. Am I going to have problems with both in a 55gal tank? I've read mixed reviews so far... not sure what to do. The LFS has offered to take the LTA back... and give me credit for it (I am repeatedly impressed by the level of service at Blue World BTW) and I'd just have the BTA... but I kind of like the idea of having both.

What do you think?