What do you all know about 5'8" 1956 Knabe grands? I know Knabe used to be a great company in the early 20's? Or, maybe I'm wrong. Thanks for the info!

At that time, the Knabe name was owned by the Aeolian-American Co., and Knabe pianos were made in East Rochester, New York. Aeolian's top-tier of pianos at that point consisted of Mason & Hamlin, Knabe and Chickering. The Knabes of the size you refer can be very nice pianos...or have the potential to be very nice pianos.

Lokking to buy or sell?

I'm looking to buy. I don't know much about them. Right now, I'm in the process of looking for a very nice piano. The guy is selling it for $4500, and I'm not sure about it, as I know Aeolian wasn't so great? (I'm I right in this assumption?)

They were a great company up until the beginning of the depression, when they went broke and got sold. Early open block Knabe's (before about 1905) are expensive to rebuild, but from there up to 1930-ish they can be very good. The Aeolians weren't as good, but they're not the worst thing on earth. Depending on condition $4500 could be a good price.

No matter what piano you buy, you're going to need a regular tuner-technician. So, start there, and have your tech check out the 1956 Knabe. Angie's List is a great place to find one.