Agree. I have 2 "souped up" Emperor 400's on our 150 and the water is great. Got them new on ebay and total including shipping was $95.00. The LFS here sells them for $109.99 each.
I have 2 aquaclear 110's on one 90 gallon, totally worthless IMO. They plug up practically every other day. My other 90 has a magnum 350, much nicer filtration, and much less hassle.
i have 2 ac 70s on my 105g and also have 2 ac 50s on other tanks. they all work great.. as for your tank i suggest 2 ac 110s. if you buy 2 filters the same you can buy foam inserts for one size filter instead of 2.