I asked the same questions here. James C gave me a link for an Encore unit. I bought an Encore Revive system which is manual and battery powered. I live outside the US and couldn't get the same recommended model delivered here...at least not quickly and not from the same source.
I have used it about a dozen times. It has not yet given me a useable erection. However, I believe it has given me excellent therapy.
I was starting to seriously shrink in flaccid size. I have achieved success all times I've used it in terms of enlargement and more importantly, blood flow. My normal state is getting larger and I'm feeling "movement" I haven't felt since before surgery. For me, this device works.
It took some getting used to but, not difficult at all. Crew cut haircut in the underwear department helps with sealing the device as does the lubricants that are included.
My normal state has gone from almost non-existent (turtle?) to almost pre-surgery. My erect state needs some more work and patience and perserverance I'm sure will work for me.
Personally, I'm a believer in these devices.
Hope this helps.
PS: James C...many thanks