I'd say Prussa.

I am not going to say they are perfect, but I think they have a good balance of ethics, openness, product quality, innovation, availability and price. By that I mean their are the best in none of them, but I don't think of anything better as a combination.

I would have said Prusa a year or two ago but they've reneged a little on their open-ness. That was probably in response to Bambu being fully closed and gaining so much market share.

The Core line of printers seems promising and a big leap towards closing the gap towards Bambu's corexy printers but haven't used one yet and I've been out of the game a little. Bambu though is probably more of a high-end appliance type than Prusas more utilitarian feel.

Prusa. And my Raise3D E2 has been solid for ~5 years. I can't directly compare it to Bambu, but it was a massive step up from the Creality Ender it replaced. It's a "Just works" machine.

I have a Prusa MK3S and it has been very very reliable. There's also a ton of mods you can download and print, which modify or extend the printer for specific use cases. They are a bit more expensive then their Chinese counterparts, but in my opinion, it's definitely worth the extra cost for the peace of mind.

I just bought a qidi printer. It arrives in a few days, so I can’t speak to the machine’s quality beyond saying it’s reviewed pretty well - but the software is all open source klipper with no locks preventing you from modifying it. The hardware itself is closed source, but if you want an open hardware machine in 2026 you need to build your own voron.

Obviously it depends on what you’re doing and what is importante to you. It’s hard to beat Bambi Labs H2D or X2D for versatility, practicality, and price. Engineering filaments are getting a lot cheaper as the market expands so it helps to have a printer than can handle those. Given Bambi Labs is so cheap compared to the alternatives customers would probably be better off putting aside the savings to buy a second printer from a different supplier when one starts to catch up.

Prusa is the most open of the printer manufacturers. They did have to backtrack a bit because Bambu copied their slicer to use for themselves and undercut them, but they're still as open as you can get in a capitalist economy.