Depends on your budget and long term brewing plans. I was very happy with a MegaPot and DarkStar burner for many years. Then I got some Keggles and a second hand Edelmetal burner. Now I have a Ruby Street single tier gas setup. I plan on upgrading to electric this year.
If I was doing it again, I’d seriously consider going with a all-in one like the grainfather / brewzilla / etc.
Latecomer to the conversation, but an electric all-in-one is a fantastic experience. I went a bit hog wild with the Spike Solo+, but the only thing I want to impress on you is that 220V makes a massive difference. Strike temp is quick, all the mash steps happen fast, boil is quick. With 120V, stick to the 5gal kettles or you'll really be feeling some pain from exceptionally long brew days.
I’ve been using a 120v 1800W induction burner for years, but will be looking to upgrade soon. It’s JUST powerful enough to boil 7 gallons or so, but it takes a long time to get there. If your setup allows for an electric brew, I think a 220v induction burner would be the bees knees personally. Extremely efficient, assuming you have electric rates in most of the US. Same might not be true for people in Europe.
That said, most setups (mine included) dont make plugging into a 220v receptacle convenient. For that reason, I’m going to a propane burner soon. Curious to see what others recommend here
I'm across the pond and use a Braumeister, takes about half an hour to go from mash out to boil, with its immersed heater coils. 230v is standard here, I believe tri-phase is 380v.