I always use the former Motion Picture Laboratories (now known as Encore Media) in Nashville. They've done tons of 35mm for me and a little bit of 16mm too.
Great folks, good rates, attention to detail, and old fashioned southern charm.
They are only about two hours north of me, so I generally would FedEx film out in the evening to them, then zip up there the next day to babysit the transfer. But I have friends all over the country who just ship film to them and get an unsupervised transfer... and all have been happy with them.
Their senior colorist John Buchanon can play the daVinci like a piano.
Fantastic Plastic Entertainment, Inc. fantasticplastic.com