I have been 100% impressed with my Yammy HTR5760. 7 channels of amplification and DPL2x for around 350. At this point in time it is a hard bargin to beat.
Most likely you won't find the Sony STR-DEXXX sound as good as(probably not even close)the AVR125. If you really want a Sony, at least get the STR-1000ES.
I listened to quite a few HK AVRs. I found that all X25 & X30 series sound similar (all nice). Not sure about the X20 ones because I have never listened to one. As for the Sony models, I have read many good reviews on the ES (elevated standard) line products, but not the DE line. No one seem to think too much of the DE product line.
I used to owe a DA4ES, to me, it was as good as the equivalent(price) HK AVRX25 models, in terms of EQ.