Recommended Filtration for an Oscar (cross posted)

I'm looking for a more powerful filtration system for my 55 gal Oscar
tank. Although I vacuum and do partial water changes every 5 days or
so, I find my current bio-wheel filters to be inadequate. I did, at one
time, have an UGF in the tank but did not like it. I could not keep it
"healthy" with all the vacuuming I do. So putting one back in is out of
the question.

So, what I'm wondering, is should get more powerful bio-wheel filters to
increase my gph filtration or should I invest in a canister filter or
something else? What kind of setup has worked well for others. I need
some advice.

Sunshyn