Interesting about your brass fittings experience... I actually found PEX piping to be way more practical in my case. Had brass fittings before, and while they held up fine, the mineral build-up was still annoying over time. Switched to PEX during a kitchen remodel a couple years back, and honestly, haven't looked back. Plus, it's easier to install and replace sections if needed. Coffee still tastes great too, though that might be more about my water filter setup than the pipes themselves...
I've done a fair bit of plumbing with both brass and PEX, and honestly, both have their quirks. Brass fittings are solid but yeah, mineral build-up can be a real pain over time. PEX is definitely easier to handle—especially if you're DIYing it—but I've seen a couple fittings fail prematurely if they're not crimped just right. If you're switching, make sure to invest in a good crimp tool and practice on some scrap pieces first... it'll save headaches down the line.
Yeah, plumbing under sinks can seriously test your patience. I had a similar issue last year and switched from brass to PEX. Thought it'd be an easy fix, but like you mentioned:
"I've seen a couple fittings fail prematurely if they're not crimped just right."
Exactly my experience. My first attempt ended up leaking worse than the original brass fitting because I skimped on the crimp tool (lesson learned!). After biting the bullet and getting a decent tool, plus practicing a few times on scrap pieces, it was smooth sailing. Honestly, the convenience of PEX is worth it once you get past that learning curve.
One thing I'd add—double-check your connections after everything's installed. Sometimes leaks don't show up right away, and it saves you from waking up to another puddle under the sink... ask me how I know, lol.
Good call on investing in a decent crimp tool—seen way too many DIY jobs go sideways because of cheap tools. Also, don't overlook pipe cuts; uneven ends can cause leaks too. Did you use a pipe cutter or just snip 'em?
Honestly, I've gotten away with just using a hacksaw plenty of times without leaks. Trick is cleaning up the edges afterward—bit of sandpaper or a file usually does it. Fancy tools are nice, but not always necessary...