I agree w/ the op, a Pentax K 1000 is a big and heavy camera compared to the MES. The K1000 is quicker to shoot in tricky light though. Just turn the lens aperture while keeping an eye on the match needles in the viewfinder. I have an MV and might buy an ME Super at some point, even if it is a very limited camera. Love their small size, and the MES has a quieter shutter and a lot brighter viewfinder than my MV.
Let's be honest, Pentax really screwed up by not putting an AE Lock button on the MES. Center weighted metering is fine for what it is, but there are more than a few occasions when it isn't going to be that accurate. That makes the camera more of an amateur point and shoot SLR, which is probably what Pentax had in mind.
If it had AE-Lock like the Canon AE-1 Program, lots of Nikons and other cameras (including the later Pentax cameras) you won't miss a shot while fiddling around w/those tiny buttons located on the top of the camera. Surprisingly, my MV's 50 2 lens is as good as the 1.7 when stopped down a bit. It makes surprisingly nice negatives. I did have to hack the lens to make it work in stopped down mode only because I got tired of not knowing what the DOF would end up being. Now I see exactly what will appear on the neg.