I'm a little late to the party, but I've made a few batches of pumpkin beer, and thought I would share.
Back when I brewed with MrB in LBKs I made a pumpkin beer and the pulp got in the bottles. It was as good as any other MrB kit I'd used.
Since then I made a few batches of NB Smashing Pumpkin extract (with specialty grains) kit, a couple with canned and one with a pie pumpkin I processed myself. No real difference in flavor between canned and fresh. I BIAB'd with as much 6-row as the instructions said I could use. No sparge. Some pulp did end up in primary. I remember it being good, but not good enough for me to make it again.
Most memorable thing about the brews was when I baked the pumpkin. I quartered it and got all the seeds and stuff out before putting it in the oven. When my wife called I told her I put the pumpkin in the oven and she was all "oh good, you cut it up and everything?", to which I responded "Uhh... what?". She thought she was going to come home to the pumpkin having exploded in the oven.
Family that I shared it with were not sold on it.
I would like to one day do another side-by-side experiment to see if the pumpkin contributes any flavor or if it is just the spices. Problem there would be that the pumpkin + 6-row would definitely boost the alcohol, and probably mess with the flavor.