I have a very simple system. I have 5.5 gallon induction capable kettle (I do 3 gallon batches). I mash in a BIAB bag in that kettle. I heat my water with a stand alone 1800W induction burner that cost $38 on Amazon in 2018. I wrap the kettle with a beach towel and walk away during the mash. About 30 minutes into the mash I start heating my sparge water in a second kettle. When the mash is complete, I pull the bag and hang it with a pulley for a few minutes. I don’t sweat getting every drop of wort out at this point. Just drain until it’s moveable without making a mess. I then place the bag with grains still in it into the kettle with heated sparge water (a dunk sparge). I stir a bit and then leave it for 5 minutes. Meanwhile the main batch is heating to boil. After the 5 minute sparge rest, I hang the bag on a pulley to drain over the sparge kettle. When it’s ready, I pour the sparge batch into the boil kettle manually. Next, I clean my bag and sparge kettle and it’s off to the boil. I use the same induction burner to boil. I get 83% mash efficiency.
My system was cheap to assemble. I like the brewing and cleaning simplicity. There two other things I think are advantages. One, I intentionally don’t have a pump because they take a bit of extra time to rinse and clean (I know it’s only a few minutes). Two, I think the dunk sparge is much easier than the pouring cups of water over a grain basket as is the case for the all-in-ones (I used to have a Grainfather).