Luxman L505u . . . why not?

I'm getting close to pulling the trigger on one of these--an upgrade from my Rotel receiver. Before I do, I'd like some perspective from the learned A'gon community. First, will it be a significant upgrade from the Rotel? What kind of sonic improvements can I expect? Second, why shouldn't I buy from Audiocubes II? http://www.audiocubes2.com/brand/Luxman/product/Luxman_L-505u_Integrated_Amplifier.html
I know On a Higher Note is the official U.S. distributer, but my budget pushes me towards the less expensive purchase option. Third, regardless of where I purchase it from, it will need a transformer to boost the power to 220. I don't know anything about the possible effects this might have on sound and performance of the component--can anybody speak to this? Is it possible to have the piece modified to accept the U.S. 110 current? I want the piece because it meets my requirements for an integrated: it's at least 100W, it has speaker A/B (I've got speakers in the kitchen and the main living room), it's got a great phono section (I play 50% records, 50% CDs), and it's got a headphone amp. Those are the features I want in an integrated. Any advice, suggestions, dissuasions will be appreciated.

Danny