Something

Something that dramatically reduces the allure of the M&P 9 at the local pawn shop is that manual safety guns with the small diameter sear spring cannot be self-upgraded to use the Apex trigger kits.  You have to send it to them for the work and that's a bit more money and a lot more headache.

The kit I'd want is $110.  The service is $185 plus shipping and handling, which thanks to the ATF regulations is significant, between $110 and $160.  So $300 to $350 on top of a $400 gun...

I can get a newer M&P that already has the larger sear spring and the kit for less.  Or a NEW one that's current production which doesn't seem to need the Apex kits so desperately.  Edit to add: Found the same model (206301) with a 2013 manufacture date on Gunbroker for $489 buy it now.  $489 + $25 s/h + $30 transfer + $110 kit is...  $654 for this with the Apex, compared to $700-$750 on the pawn-shop gun.  Edit to add even more: A local dealer has an M&P 9 Pro Series (which I hear basically comes stock with an Apex trigger) for a mere $529.  Far cheaper than modifying.

The main problem is that Smith and Wesson doesn't sell the sear housing block for the guns with manual safeties.  There is a rumor on a couple of forums that the current revision of p/n 390900000 works with the manual safety.  I do not know, but I've ordered one from Midway to have a look at the right side of the block.  If it uses the small pin ejector and has a rectangular cavity for the safety plunger, it might just work.

The reason for the rumor is that the M&P 45, where the thumb safety is more common, switched over to a common housing for all the non-internal lock variations.

On the gripping hand, the stock trigger is not really that different from my Hi-Power and I shoot that rather well.  The Lovely Harvey's new gun appears to have such a stock trigger.