You can get a lemon from almost any manufacturer. I own 2 Acer laptops and have been very impressed with their build quality. I think that they are an excellent choice when it comes to bang for the buck.
I didn't know they were "much maligned" but I gues I am not disagreeing with you as you are saying you think they're better than Lenovo. One other note on Lenovo though: The Thinkpad line is excellent. Still the best laptop keyboard I've found.
I own two acers as well.
Acers aren't built to be used like enterprise laptops, that's for sure - mostly plastic, stiff mouse buttons, not really sleek or slender. Their displays also tend toward the lower-res and heavy side.
But they do work well, especially for the money. They are well designed, and the (mostly) good design makes up for the lower-tier parts used within.
The thinkpad line when made by IBM was THE standard for enterprise laptops, with the Dell Latitude line a close second. Today, they are decent, but a far cry from what they used to be. The plastic is much thinner and weaker; metal hinges have been thinned and reduced.
To anyone buing refurbs, I'd strongly recommend enterprise class refurbs.
After seven years of SD, I've come to conclude that Slickdealers are protein-powder guzzling, pistol packing, cheap-ass video game nerds.