I thought Champix was great, I gave up for 6 months or so last year and stupidly took it up again for reasons I can't recall now, I had a few tries with patches but it just didn't work or I didn't let it work (take your pick).
Start of the year I went on Champix along with a co-worker and we've been smoke free since the end of January, I have had 1 or 2 but that is whilst fairly heavily intoxicated, not much you can do about the will power then.
I found the night tablet would knock me for 6 for an hour or so, I'd be lying in bed and just spring to life as if I've had hours of sleep.
The morning tablet I found if I didn't have something to eat within 20 minutes my stomach would get really twitchy and almost to a point where I was going to be sick, this was just something I got used to it.
What really amazed me was you get to a point when your taking them you think I don't want this smoke but I will anyway, you still need will power as I was more or less found I was smoking purely because it was the habit thing. Even now there are certain things which I do which spark me to thinking I need a smoke but it doesn't take much to overcome them (it does get easier but don't get sucked in and think like me that 1 won't hurt).
Be very prepared to whack on some weight although it was the least of my worries at the time, in 3 months of quitting I whacked on 16kg which was disappointing but I'm slowly peeling them off again with plenty of extra.
All in all I couldn't be happier, I am back on my bike and doing 8km each morning which for the size of me I think is a feat in itself.