A cheap A77 grip alternative spotted on eBay.

Vertical grip:
A SAR reader sent me the link to a much cheaper [shoplink 12857 ebay]Sony A77 external vertical grip on auction on eBay (Click here)[/shoplink]. As you see it costs much less than the official Sony VG-C77AM Vertical Grip (here at Amazon). Question is, does it work at least nearly as good as the official grip?

Reminder: Sony extended the US deals til September the 1st:
1) The $100 off on some camera+lens combos (Click here).
2) Price drops on a long list of Sony camera accessories (Click here).
3) $80 off on the A65 (Click here) and the A57 (Click here).