i juste change my w505 for a z110bt
the w505 dont have gps by default, you need to buy a NEV-P1,
and this gps are a shit compared to z110bt
the w505 are a very good stand alone HU, but you need to purchase all option separatly, ex: GPS, Bluettoth
and the price are very similar with all option
if your goal are SQ system, the w505 with PXA-H701 are very very good
but if you want a very good multimedia HU with a good GPS, the z110bt are far away the best of both
and if you want ad more SQ, add a Audison bit.one processor