I have an air mattress and a cot- in 2011 I actually had BOTH as I had no one to split my tent with. I tended to gravitate to my air mattress, but my cot was great to drag out under the EZ Up for a mid morning nap.
My air mattress is a $40 queen self-inflatable from Ocean State Job Lot and it's lasted me 3 Roos and various other fests and camping excursions. It keeps it keeps it's air very well and I believe it's still available at the same price. My Coleman cot was also something like 40 bucks and it's not too comfortable. I bring it to fests/ camping when I have to drag my gear a distance or it's only one night and not worth the hassle. Most people will say the cot is better, though.
My tent.. ehh. It's ok. It's also Coleman or some other everyday brand. No issues, but I don't preach it.
EDIT: My cot might be this as it has a mattress, but the design is different. Coleman Ridgeline III Camp Bed
The air mattress is Intex, although I now see that Job Lot is a Northeast store.