After 14 years of using a mediocre Audio Technica LP120 with the stock cartridge, I upgraded to Rega P3 with an Exact 2 cartridge about 3 years ago. Considering, that I'm not DJing and listening for pleasure only, I'm extremely pleased with my current setup. If anything, I'd dip my toes into the MC arena first before upgrading the deck. I'm not one to cycle through upgrades - both because I don't have the disposable income or desire to churn through equipment but because I haven't felt the need to.
Maybe, I'll entertain an alternate setup like the Technics 1200 for swapping cartridges for fun once I get my listening library/den built in a few years. But will keep the P3 as well.