I've had Harbor Freight's version of the X2 mini mill for about 10 years, same as Grizzly, Sieg, Micro Lux, etc. I bought it with a New Years Day 25% off coupon, back before they had so many exclusions on their coupons.
It's handy, but for sure has its limitations. I've done some Little Machine Shop upgrades, the gas strut conversion is very worth it, I'd never go back. I bought a bunch of iGaging DROs off of Amazon or eBay, made my own adapters/mounts, instead of buying the kit, took a lot more time, but was a lot cheaper.
It's a mill, but it's not really a precision tool, better than an angle grinder sure, but the lead screws have so much back-lash, using the gradiations on the X & Y knobs is about impossible. There are aftermarket ball screw upgrade kits for them, I've toyed with the idea of going that route, would be pretty much mandatory for a CNC conversion. For the time being the iGaging DROs make up for the lack of precision from the knobs.
A lot of folks complain about the plastic drive gears, there are upgrades, Little Machine Shop sells a timing belt drive conversion. I still have my original gear set, and have never had an issue. I do my best to make many light passes, and don't over load the machine, staying well within its limitations. I'd rather keep the plastic gears as a fuse.
There are more options now that these things have become so popular, but the X-Y table uses a less common 7/16" T slot, don't do like me, get your first ever mill, assume they're all the same, and buy the more common 1/2" T slot clamping set.
I'd for sure buy mine again, I don't regret owning it, it's aided in several projects, and has provided new projects as well. I've done the mods mentioned earlier, but also built a stand for it with built in storage, and have designed it so I can add a coolant/cutting fluid system to it.