it all depends on what you want... yes, a limited slip is better for the snow/ice as a locker will tend to push you in a straight line and any touch of the gas in a corner will you a 'spinnin... But that doesn't stop me from getting in my fully locked truck and heading out in every snow we have. It just takes some cautious driving and knowing how your vehicle is going to react.
If you do a lot of driving in snow/ice with very little offroad, LSD is probably a better choice. If you do a lot of offroad or plan to, you might wanna look at a locker... i don't care how good of an LSD you have, a locker is going to take you further off the road.
But as far as LSDs goes, the Truetrac is a good one... far better than your stock unit. It uses gears as opposed to clutch packs which means it won't get worn out as you use it.
Another thing to consider is install costs. The Truetrac is a carrier replacement and will need to be installed by a professional as gear resetting will be required (you're looking at about $200 labor for this). A lunchbox style locker such as the Powertrax No-Slip or Lockright will cost just about as much as the LSD, but can be installed by most weekend mechanics in a few hours.
1995.5 Isuzu Rodeo - SAS'd and SOA'd, sitting on 36x12.50 TSLs, D44 front, 14bff rear, locked by OX and Detriot, suspensions by Jeep and Chevy, high steer conversion, 5.13 gearing and Teralow in the case.