I've always liked my Sony HUs - VERY clear sound IMO.
I've had 3 so far... and I've just got myself a GT300.
This is the most basic one I've had... so I miss some of the sound adjustments I was able to make on previous ones I've owned - this one has only a 3 band EQ wheras my previous ones all had 7 bands.
That said, it's great for connecting up to various things:
Wired remote output, so compatible with stalk adaptors.
2 pre-outs (Front & Rear/Sub)
Front AUX in
Changer ready & Ipod adaptors readily available.
I've got it wired up to infinity co-axials at the front, and a slim sub powered by a 700W alpine amp. I'm very pleased with the results.
Go for it, ex-demo units available for £60!
http://caraudiosecurity.com/shop/product/products_id/7237.html
I bought mine from them and it was mint (apart from missing keys).