I'm an indoor brewer who brews 3 gallon batches on the stovetop. One of my only frustrations with my current setup is how long it takes to get 4+ gallons to a boil on my stove, and maintain a strong enough boil at that size.
I had started to look into electric heat sticks, but most of the info out there was for DIY stuff. I know enough about electricity to know that "DIY" and electricity aren't something I want to mess with. At least nothing in the kilowatt-plus size.
So the other day I ran across one of these.
I decided that the price was right, so I gave it a whirl. While it's not exactly "how did I ever live without this" good, it's certainly well worth the money.
My stove generally takes 40-50 minutes to get 4 gallons of wort from mash temps up to a boil. With the heat stick helping out, I hit a boil in 25 minutes. I was able to maintain a healthy (but not explosive) rolling boil without having to do the "lid half on" trick. This is completely subjective, but I felt like I got a better hot break using the stick as well. It could also help cut into your time to hit strike temps if you're starting from room temp water (I use hot tap water from my sink, so that's not an issue for me).
As a test, I used the stick alone to heat 3 gallons of water in my kettle. I got it from 60F to 160F in 35 minutes. So you could even potentially heat your strike water right in your mash tun with one or two of these. Overall, if you're brewing more than a gallon or two on a stovetop I'd really recommend one of these.