patricej

my advice would be to go with either a Brother, Babylock or Janome brand.
you are more likely to have certified service/repair providers within a reasonable distance.

look for the biggest maximum hoop size available that fits your budge.

whether or not a PE800 will help with quilting depends a lot on the size quilt you usually make.
it's pretty small so anything larger than a crib quilt is going to give you fits unless you use one of the many quilt-as-you-go methods.

(with QAYG you can do just about any size quilt you want.
just make sure you plan assembly so that all the weight of the growing quilt is to the left of the machine.)

biggest challenge is getting everything to fit inside the harp while also getting the weight of the quilt off the hoop.

only a few years ago, it was difficult to find single-run embroidery patterns good for quilting.
(double and triple run motifs can get seriously out of wack unless the quilt's weight is perfectly distributed and off the hoop.)
pattern creators seem to have finally seen the light, though, because there are an ever-growing number available in a wide range of prices.

the first place i check for single-run motifs is the embroidery library (emblibrary.com).
they have a lot of choices in sizes that will work well for the size hoop you are considering.
they are also remarkably inexpensive.

as mentioned by sandygirl, amelie scott offers several collection of single-run patterns. they are reasonably priced, given the number of patterns and size options in each package.