I use gators and love them. Cannot use them with plug. The problem with a plug is, you have to cut the grass fairly regularly, and not wait if it gets high. I got mine from Agri-Supply, 2 blades came shipped for about $26. The same blade at Sears were like $75 or so.

I use Gators with the mulch kit on my 38" deck (LX178) and it works great. I use the plug so I don't spray grass all over the driveway, road, flower beds, etc. (yeah, I live in town). You will still get the best results by mowing frequently (cut off no more than 1/3 of blade height) and not too fast (although I cut at ~5mph in the back where the grass isn't quite as thick with great results). It is a relatively cheap experiment, so try them with and without the plug to see which way works best for you.