BeerBorg

I have a few stainless pots, but either material is fine. My 4-gallon pot I brew with for 2.5 gallon batches is a Polar Ware unit that I won in a raffle back in March, and it works great. Had I not gotten that one, I would have opted to buy an aluminum one because it's cheaper. My 3-gallon pot I now use for heating sparge water that I bought when I first started brewing BIAB, and I have a 5-gallon pot that I got at Marshall's on clearance when I needed something bigger because I was starting to do full volume all-grain boils and 2.9 gallons of wort in a 3-gallon pot is a boil-over hazard that I didn't want to worry about anymore. The bigger pots take longer to heat up, but in that regard, you just need to make sure your heat source puts out enough energy to get a boil going in little time with as little fuel as possible.

TL;DR aluminum is cheaper, stainless lasts longer. Both get the job done.

I bought the 40qt. It's quite solid. I also bought the lid, and a quick read digital thermometer. If I can figure it out, it all can be paid for with thank you points from my checking account.

If I were you, I'd get this pot temporarily, and get a SS afterwards. You can use this pot as a hot liquor tank for recirculation later. I bought a "blem" 40 gal SS Brewers Edge pot for $90, but kind of wish I had waited for something a little thicker. I'll probably get a SSbrewtech pot soon and use the Brewers edge as a mashtun or hot liquor tank.

Thanks Los, I prefer aluminum, and BIAB.

I've got a 62 quart stainless steel Bayou Classic with a matching grain basket in my eBIAB setup. So far I've done 1.053 - 1.058 batches of ten plus gallons and that's pretty much pushing it to the limits with twenty three pounds of grain. The bigger the pot the bigger the heat source too but in the end it's your beer and up to you whether you use gas or electric, stainless steel or aluminum, ten gallon or five gallon batches.