I have a mash and boil no pump version, and I love it. On that system you will see the read out on the display swing 5 or 6 degrees during the mash and typically the element will kick on once or maaaaaybe twice. However, I keep a separate thermometer in my mash for the entire hour, and over the course of an hour I only lose 1 degree from the grain bed and I do not use any additional insulation or anything else. I do manual recirculation and stir the grain every 15 minutes during the mash. My last three brews have all been over 80% brew house efficiency. The only down side in my opinion is that it takes a little while to come up to temperature, but I use that time to do other things. There is a learning curve to get your process dialed in, but once you get in the swing, it's a breeze. I love the simplicity and ease of use.
The mash and boil is not set up for doing step mashes using only the element. But I think if you did the steps using hot water additions rather than relying on the element to heat things up, it would work fine.
Between the anvil and the mash and boil I think it comes down to how much volume you want and if you need or want all the extras that come with the anvil system. I do mostly 3 G batches, already had a chiller and didn't want the pump and all its hassle, so the mash and boil was the right choice for me. It is easy to do 5G batches in too, unless you are trying to do a really big beer. The mash and boil has, I think, a16# limit in the mash pipe. My only other advice when using one of these systems would be to get yourself a biab bag to put in the mash pipe. It makes the sparging much easier.
Cheers!
