Sammy will be missed in Chicago. As far as his talent, I think he's is eerily similar to Jeff Bagwell. Both are well past their primes and are declining at a steady rate. But they can both still smack the hell out of the ball.
As far as their status with fans, I'd like to say that it's mostly the fault of Chicago fans. Cubs fans, as reknowned as they are for loving the losers and always selling out Wrigley despite all the losing seasons, are brutal. I remember the chants of "HEE-SOP-CHOI" whenever Derrek Lee was at the plate last year. Lee was struggling, and Choi HAD ALREADY BEEN TRADED to Florida. So mean to Derrek.
Sosa was booed more than anyone last year, and every strike out pissed off the fans more and more. By the time he finished the season with a .253 average, he was frustrated and pissed as well. That's why he left the stadium in the last game of the season. And why he bitched all season about this or that. The cork... well, no one can really explain that.
The difference between Bags and Sosa is that Bags would never walk out on the team like that. He wouldn't bitch about being dropped in the order either.
Of course, Astros fans would never boo Bagwell because they actually have respect for ballplayers that have meant so much to our team. It's a vicious cycle, and I'm happy for Sammy that he was able to pull himself out of it. He knows, as does everyone, that Sammy doesn't have what he used to have. And fans up here would never have forgiven him for it.