has anyone had experience with either the ikea smaklig / otrolig cooktops
is the otrolig worth the $300 extra?
Can't speak to those, but here's my general advice for induction cooktops. The way they do power levels is they pulse power on and off (PWM) with the duty cycle (the time that it's on) varying to give power levels, this is fine and good ones should do this at a fairly high frequency. The problem is that cheaper ones (it's cheaper to do it this way) pulse at a very low frequency, like 0.1Hz (not a typo). This basically means that you'll have something like full power for 6 seconds, then completely off for 4. This makes it fairly annoying to simmer stuff properly as it'll try start to boil over in that 6 seconds. If you can turn one on, you'll notice this happening fairly quickly.
Do they allow you to try the cooktops in store?