I purchased a used LEO 45 ACP with night sights. No safety. It was a 1.0. The nights sights didn't work well, but I couldn't complain as I wasn't expecting night sights.
The only upgrade I performed was adding an APEX trigger kit-much muddling as the kit is not cheap. That turned the gun from average to GREAT. It is by far the firearm I can fire the most accurately at distances greater than 10 yards. I have a Shield 45 and an XDM 45 and 2 ATI 1911 45's and one RIA full length 1911. The M&P though, is still the best. Whatever law enforcement officer owned it previously took care of it because it feels good in the hand, the sights were easy to adjust, and there wasn't any real holster wear.
I just recently purchased a 9mm M&P 2.0 with a 4 inch barrel. I will say, the stippling is AGGRESSIVE. After a number of range sessions and getting a bit frustrated, I broke down and ordered the APEX trigger kit along with a 1.0 backstrap. Hoping it works just like my M&P 45.
The only recommendations I would make is to rent one and pay attention to how the stippling feels on your hand. It is aggressive, and while holding it doesn't feel that bad. After a firing session, it can hurt the palm-depending on how many rounds you fire-after 100+ rounds. The other recommendation is the trigger kit. The 2.0 has a descent trigger kit, but I have found that I do much, much better with the APEX trigger. YMMV.