Well, since HP has been specifically mentioned -- they're highly variable. Some are winprinter junk, others even have full PostScript support built-in alongside PCL. For instance, the LJ3030 multifunction at the office I'm working at is pretty much a dream with hplip*, the scanner function basically works flawlessly (see footnote again), etc. Other models are... not so good, and you pretty much have to research on a case-by-case basis.
The one thing to be aware of is that, with any HP laser, and with for instance the Samsung model mentioned, you're getting a new drum in every cartridge. This is sort of wasteful, but the alternatives are as follows:
* Kyocera is the one brand using a permanent drum. If I understand correctly, this is intended to be used only with the official Kyocera toner that contains a tiny bit of ceramic to slowly 'polish' the drum as you work through the hundred thousand pages or whatever it's rated for. I have no idea how the drum stands up to having envelopes, staples, etc misfed or jammed in it. [Edit:] FWIW, I did research these and IIRC *nearly* all models are straight PostScript machines, except for one or two on the low end. However, above the low end, you're looking at $400+ printers.
* Brother, Okidata, and some other manufacturers offer models with a separate toner and drum. This is sane as far as the waste stream goes, but the problem is that you wind up spending $50 for the printer, at least $30 per toner, and invariably the drum starts going within a year and costs $200+ to replace, plus downtime and headache (if you can't bear to spend >$75 over the best online price to replace it at a retail store).
In office/multiuser environments, I find it's just not worth it to deal with the separate-drum models. People will invariably do at least one stupid thing (or find a way to have one truly heroic jam) with any machine at least once a year. With a drum-in-cartridge machine, you'll have spare cartridges on hand, which, if you purchase remanufactured, are only like $30-$40 per >3,000+ pages. With a separate drum, you're saving $10 per toner that usually only lasts up-to-3,000 pages, then you're spending it back and then some on drums.
For home, if it's convenient to get a Brother (often down to $40/printer retail, most 'quietly' support either PCL or PostScript if you ignore the proprietary drivers) and treat it with kid gloves, that might be an option, but you'll still want to wail and rend your garments when the drum starts to go.
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*Aside from the neverending puzzle of getting labels to print with perfect registration, and the fact that the machine it's connected to is still running Ubuntu 6.06 or whichever "Dapper" was, so I don't get to enjoy the full benefits of newer hplip and improved SANE support until I can upgrade the machine. Nonetheless, the scanner with the ADF really does come in handy if you need to do OCR (and gscan2pdf + tesseract now works more-than-survivably for basic OCR of English text)...
[Another Edit:] The particular Samsung I mentioned is a networked, PostScript machine that's often available very cheap; most of the USB-only Samsungs, and possibly that new, trendy, 'piano'-shaped wireless model, use an obscure Samsung language conceptually equivalent to PCL. There seems to be a sturdy open-source filter for it, now, but at no more than $20 difference, it was a no-brainer to get the model that just sits on the network and speaks IPP, lpd, etc. If you want a direct connection Samsung, find the driver first and then pick from the list of supported models.
