Stirring VS Recirculating? Is one better? I think the motors vs pumps and the effort required are probably equal. So does anyone see a definite benefit of one over the other?
The biggest difference is that stirring alone doesn't allow you to adjust your mash temp. A recirc system usually runs through a heat exchanger. Stirring might in fact benefit a recirc system, though I would think if you have a good tun design, the grain is evenly rinsed by the recirc water, so it shouldn't be necessary.
My stirring setup will be used with a steam infusion system. I decided to go with steam after I saw a recirculation system in action. I wasn't impressed by the temperature fluctuations during recirc: The wort sitting in the plumbing cools when the mash is at temp (and it's not circulating), then the temp in the tun drops a few degrees when it kicks back in. Is that really an issue? Probably not, but add to that all the plumbing required and I decided to go a different direction.
With steam, I can get a pretty good temp rise, on the order of a couple of degrees a minute. Not sure what those RIMS/HERMS folks are getting, but from what I saw of the system I was on, it was much slower. Also, I wonder if those enzymes trapped in the plumbing aren't better off in the mash. For larger batch sizes, the amount of liquid in the plumbing is probably negligible. But, for 5 gallon stiff mashes?
Then there's cost: those pumps are expensive. You can get a windshield wiper motor to drive your mash mixer for $15. (But, I suppose if you've got a pump anyway....) And you need two temp controllers and stainless fittings for your plumbing.
I dunno, it's probably more a philosophical debate than a technical one. Once you get any system dialed in, you can achieve great results.