I also prefer to use Flying J truck lanes for all the reasons that have been mention previously. Sometimes they may be a penny or two higher but the ease of access, for me, is more than worth a dollar or so per fill. Unfortunately, I have a MH that does fill very well with the high flow nozzles but I cut a piece of foam into a wedge shape and use that under the handle. In my case it's simply a poor design and there isn't anything I can do to change it. Since I very seldom take more than 80 to 90 gallons at a time, it's not to big a deal.
One real nice feature is being able to look at station locations on their website so I can plan my fuel stops along my route of travel.
As far as being crowded, I think I've only had to wait in line once or twice and that is never very long so I don't fret about it.