Bench Press vs Smith Machine

The last few weeks I have been doing my bench presses on the smith machine, mainly just to switch things up. I've noticed a little bit more of a pump from doing it. It also seems I can really keep my form in tact with heavier weight using the smith. 

I've read on the bodybuilding forums though that the smith machine can cause shoulder problems. Is there any truth to that?

Basically, aside from the increase in the amount you can lift, are there other benefits that the smith machine offers?

Depends how you do it. On the bench press you usually don't want the bar to move straight up and down. the  bar should start vertically over the shoulders, but it should touch lower on the sternum at the bottom. With that starting position on the smith the bar will come down to your collarbone area which makes it what they call a a guillotine press which causes supraspinatus tendon impingement.
 
To protect your shoulders you should make sure the bar touches your chest at around nipple level at the bottom, and don't flare out your elbows.