problem with IDE to USB adapter

greetings,

i've just bought an IDE to USB adapter lead from ebay, and it appears to be very temperamental ... it takes many attempts to connect a drive, and switching off and on etc. does anyone else have success with these types of adapters? should i expect it to be so temperamental? i also suspect that it could have damaged one drive as it'll no longer power up... just wondering if anyone else had had problems with these. i've used one before that always seemed to be fine.

any advice appreciated!

cheers