Wnted: advice on which Electric conversion kit to buy...

First I wanted a pre-made electric bike, but after a mess trying to
get the one I wanted I considered getting a kit for my 7 speed
Schwinn. I have been researching and I am having trouble getting real
information on which kits are better.

I have looked at wilderness, bionx, and others, but keep coming back
to the Bionx. I know they are spendy, though, so I was hoping for
some expert opinions before I bought. I am a larger rider, near
200lbs, and would like to get exercise but can't do the hills to work
without having to bring extra clothes and stuff to wash up. Also
would like to be able to go faster than I can on my own.

Thanks in advance if anybody's got an opinion.