I can't speak to the less expensive printers but the Prusa MK3S is really a well-engineered device for the price. A lot of thought and refinement has gone into the incremental evolution (for example, I had an MK3, and while it was OK, it's clear the MK3S has a much better extruder design that makes maintainence easier).
Some people prefer the fast shipping and no hassle return policy of amazon while not having to give your credit card number to another company. 3D Printer makers have been known to be hard to work with when it comes to DOA/broken hardware. But that is a good savings!
The Elegoo Mars Pro is slowly shipping now. I just got one. It's $300 and a worthwhile upgrade over the regular Elegoo Mars. Best to wait for stock to catch up with demand. Spring Festival is over now so they should get better stock soon.
If you want resin, check out the Elegoo Mars. https://www.amazon.com/ELEGOO-Photocuring-Printer-Off-line-P...