Moab is just a crazy place. I tend to go every April and every October, trying to avoid everything in between. (though the past 3 years I have made a may trip as well). April and October are Ideal if you're out camping, but you definitely get rain.

I went November 2010, for my 30th, and I was shocked at how great the weather was. I'm really surpised more Off Road groups don't plan around fall, instead of spring.

I'd vote, but I'm a non-commital type, whose only time making it to the isuzoo was the weekend after I bought my VX (and I'm only 3 hours away). I Loved meeting everyone, and had the best of intentions the next years, but a baby, a 1 year old, and this year a 2 year old got in the way. (I'm not in control of my life)