I guess this is where I'll jump in... Mechanix being the UFO album I checked out just a few days ago.
Going way back in time to '93 and the glory days of Headbanger's Ball Europe, I remember seeing the live version of Lights Out from the Roundhouse on there. It didn't make an impression at the time since I was strictly into all things metal (it would take having my mind blown by Van Halen's Me Wise Magic in '96 and buying Best of Volume I to catch the hard rock bug). Fast forward to four years ago and my soon-to-be girlfriend sharing a live version of Space Child on facebook. I somewhat liked it and soon afterwards came across the fact that Love to Love was Steve Harris' favourite song. Well, hearing that one was the ticket. What an incredible tune. I got the collection of the first five Schenker albums and Strangers in the Night. After hearing all that great material I realized that UFO had slowly crept under my skin. That's something of a rare, precious thing with bands nowadays.
Prior to reading this excellent thread I'd only checked out Walk on Water and Covenant of the later albums and the first three MSG ones. Prompted by this I've been finally discovering the Chapman era (and MSG's One Night at Budokan, hell yes). It's been a pleasant surprise and as expected the thought I had of Schenker being irreplaceable was naive. Paul's a perfectly fine guitarist in his own right. Different, yes, but very tasty and a good replacement.
Although I've enjoyed pretty much everything I've heard so far my sweet spot with UFO falls around the time of Force It and No Heavy Petting. I'll get around to the first two albums eventually, but as of now I'm still not ready for that.
Judging by my first listen of Mechanix: it's uneven, but still my fave so far of the Chapman albums. I especially liked the Van Halen-esque guitar tones which give it a nice edge compared to No Place to Run and WWI. The album cover is hideous and cheap looking however, so much so that it must've had an unfavourable effect on how I viewed these post-Schenker albums. There's a lot of things that could've been done artistically with idea of "UFO mechanics".
A great band and a great man, both worthy of a listening party. Cheers, TAC!