I've used the march-809. It's flow rate is a little anemic, but it works. I just purchased a Little-Giant 3-MD-HC, which is reported to have about twice the throughput as the 809. It is also a centrifugal mag-drive pump, like the march, and comes with a Ryton head (similar to the March plastic one).
The Little Giant pumps are rated to 200F max. Maybe the same materials but not the same rating. I have th L.G. TE-3-MD-HC and have used it for about 60 batches over 10 years. The impeller has a black carbon bushing that just broke and a new impeller is $46. Might be good to have a spare or another option. I'm going to try replacing the bushingor part of it with a stainless steel homemade bushing and see if that works.
The pumps are ok but I would like to see a higher flow rate. 15-20gpm. With hoses and fittings and 3-5 ft of head in the system, the flow rate is about half of the rating. So I'm looking for a bigger pump, in the meantime.