The patcher is mentioned above, not sure to which version you're referring since there are 2; the DLL hook and a patch that messes with the system files directly (and breaks with every Update). I prefer the former .
I personally just use OldNewExplorer + Aero Glass + StartIsBack++, because i just like the Aero look from Windows 7 and classical Start Menu from 7. The UX theme patcher is only necessary for some fancy custom themes as far as i know, but still, nice guide!
I read somewhere(maybe some promotional post etc) that it is supposed to be more stable because of its "safer approach" instead of relying on modifying system files.Anyway its $5 program so might give it a try in future but only if I move to win 10.
I've stopped trying to get Aero Glass to work on Windows 10. It functioned pretty well for about a year and half I'd say. After that bigmuscle's Aero Glass stopped playing well with Windows 10. At least in my experience.
The DLL hook doesn't modify system files (unlike the old direct files patch i never really used, needed to restore originals before Win Update), as the name implies it hooks at a certain point into the theming process. Never had issue with the hooking method. Biggest problem is the Symbol update after some CUs in WU, the free version doesn't support the automatic download the paid version has. Didn't have much problem with the latter.
That would probably be it. I've never had the paid version so eventually I just stopped trying and moved to a theme I found deviantart. It's not an Aero theme, but you only get so far with for free.