I was on Remicade for about a year and a half and had no real side effects (weight or otherwise). The worst of it was being tired after the first few infusions, but that was more likely due to the iv benadryl they gave me beforehand to prevent a reaction (I'm pretty sure they also gave me tylenol before hand). Remicade induced my first remission. The only reason I stopped is because it seemed like I was entering another flare. My doctor wanted to get a capsule endoscopy to see what was going on, but my insurance wouldn't approve it, even after my GI fought with them for a few months. There are risks associated with Remicade and since I appeared to have stopped responding to it, my doctor and I decided to stop it. about 6 months after stopping it, I finally got approval for the capsule endoscopy and it showed that my crohn's was actually still in remission -- it turned out that I had IBS on top of it. If it came to the point where I needed another biologic, I wouldn't hesitate.
As an FYI, I know a few people (a colleague, a child of my mom's friend) who have entered and maintained remission via remicade alone (neither of them had side effects either). It was their stories that made my decision to try it easier. I was still nervous, but excited at the prospect of remission too.
I hope your experience is successful and side-effect free too.
Melissa