I've been on methotrexate by weekly injection for five years now and I must say it's been the drug that has worked the best for me. It gave me two years of absolutely brilliant health - no symptoms of Crohn's at all! I WAS NORMAL! However, as time went by things began to flare up but by increasing the dose this seemed to cure things up, until last year when I went on Infliximab. And although Infliximab has saved me - it hasn't been as brilliantly effective as methotrexate was in the beginning....but everyones different aren't they...I know that methotrexate hasn't worked for some people...but that doesn't mean it won't work for you.
As for side effects, I ain't going to lie it's the nausea...but again people experience this differently. Some people are physically sick, whilst others feel a little sick the day after. With me, some weeks I will hardly feel sick at all and then the next it can be quite irritating. And although I hate to admit this I do think a lot of my nauesness Is psychological - i start feeling sick before I have even had it! My advice is to try and not worry about it - if it works well for you it is worth it!
Hope this has helped a little....