The Avantco 3500W induction unit rocks. That's my main rig for indoor brewing. I brew 2.5 or 3 gallon batches on it, boiling between 4-5 gallons. No elements to fuss with, avoid from scorching bags, or break. I have brewed 5 gallon batches on it a couple of times, no problem.
I use BIAB with a recirculating mash, using a pickup tube and pumping back up through the lid of my kettle. I keep the bag off the bottom and out of the pickup tube with an inexpensive stainless rack from Amazon.
The Avantco is cool because it has a variety of temp and wattage settings. It's not super precise temp control, but it does let you maintain a mash temp with only minor babysitting. After using propane burner and 110V heat sticks, it's by far the best brewing experience I've had.