Switch to Mac? (yeah, I know)

You can certainly throw a lot of money at specifications on paper, but whether that translates in to audible results I'm not so sure. Maybe your friend with the Apple gear knows what he's doing. If you know your stuff it's not too hard to get good sounds from tracking to mastering. But there's a lot to know and get right. Equipment choice is just one part

There's a point of diminishing returns where that ceases to be true I think. To get technically better preamps and converters for my RME UFX I can go to Black Lion and get an upgrade. I can do the same with many of the top brand equipment but once you get to that level I think the bigger difference will come from your skills not your equipment.

UA are not the only game in town and I wouldn't make a claim that they own the Best out there label. As far as PCs go I don't think there's many bits of equipment that won't work on that platform. As for Thunderbolt, it too gets discusses often but it neither records easy or makes your recording any better. If you have a need to record more than 40 or so channels at a time then it might make sense but until you're in that situation there's a long way to go to saturate bandwidth provided by USB2 or FireWire 400.

If you're not happy with RME then brands like Lynx and Apogee are just 2 other well regarded names. What are you I/O needs and what is your budget are 2 determining factors. If you can define the former and have no limit for the latter then I'm sure people will help you spend your money. But if you're a hobbyist moving into a new direction I can't see much of a problem with some of the gear that folks here use.

I'm certainly more than happy with my RME gear and I've never had anyone say to me they wished I'd had better sounding gear when I've delivered a mix or master for them. The only area where I'd like to spend more money is microphones but now I've retired I'm reluctant to do that as there's little return.