Usually, serial connection on a DMM is used to log data on the computer to draw trends.
I currently have a
Protek 608 at home and I'm quite satisfied. My father have the model "below", the
Protek 506 and I think I prefer his : better layout of the functions and Power is on a push button, not on the main dial. He can let the dial at the function he uses often and only press the power button...
A feature I really like is temperature... it's always useful to have a thermometer for up to 1200°C :-) No joke... I wanted to test if my oven was properly calibrated: My mother though it had 50°C error... No! it's ok.
The only thing I changed, and it's because I had better ones already at home, are the probes. The included ones have wire not flexible enough for my use.
If you search a bit on the net, I'm sure you can find a few good deals for these... ebay has some too.