hi bloomingchick,
yup, my achilles were a problem, too; coudn't stand on tiptoe w/out feeling like they were going to snap.
i've seen the yogatoes knock-offs, and they're definitely not the same. go for the real thing;
altho it seems like $$$ for a bit of silicone, they last indefinitely and it's cheaper than just about anything else you'll try for your achy feet.
btw, here's a link to some info about my experience w/ them:
http://www.plantar-fasciitis.org/talk/topic9-15.html(scroll to my post and then follow the links w/in it. more yt posts on later pages.)
the fitflops look like a good concept (and have good reviews), but if you're choosing one or the other, i'd go for the yt, since you can wear them for more extended periods - and on the couch or in the tub!
my shoes? birk's in summer, dansko clogs spring/fall, "barefoot science" inserts (got them from hsn) in my no-support winter boots. in the house, my feet are perfectly happy barefoot or in socks, nowadays.
best, gina