@adurerca I wish I had kept my original GFA 535.
I purchased one a couple years ago in great shape. Always wanted one in the 80’s. It was ‘fine’, the original Pass version. But then replaced it with a B&K 125.2 original and unloaded the Adcom quickly to an Adcom devotee. The B&K was so much better in comparison. Much warmer, deeper, and everything just sounded musical, probably because it uses mosfets. The Adcom just sounded dry, hard, and analytical. Got that desire out of my system.
Now a vintage Belles 400A replaced the B&K. And it is quite a keeper. Does everything the B&K did with more of everything. Hated to sell the B&K though.....not so much the Adcom.
To the O.P. ; personally, I would go with a separate phono pre, this is one thing I believe should be consider upgradable as a separate. Personally I like separates, but also know there are good integrated amps out there. For $700, you might look at the IOTAVX SA3. Never heard it, but has gotten very good reviews for the money, and would come in well under $700, so the Mani would be a nice phono pre in addition. Or, think used.