ProntoPatent is a cool program for MacOS that downloads patent PDFs from the USPTO. Simple, but works well. You may also wish to check out
Patent Grabber, which seems like it's been around longer, is a bit more sophisticated and is slightly less expensive, but in initial tests I liked the simplicity of ProtoPatent. Maybe I'm just persuaded by good design, which PG doesn't seem too concerned about. I think I'll try both for a while & see which one I like the best before purchasing.