Overall, the time it took to come up to temperature was longer than what I have experienced with other equipment, but it wasn't unreasonable. This can also be mitigated by adding hot water from a tea kettle to bring the water bath up faster.
Using an external thermometer, I tested multiple spots in the bath for temperature variance, and found that overall the SideKIC kept temperatures to within .7ºF. For 99% of the cooking you are likely to do, I think this is totally acceptable. It is also important to note that there are limitations in accuracy with thermometers, and the temperature range didn't exceeded the margin of error.
The initial heatup can be time consuming, but the accuracy and stability is totally fine for most home use. You might want to be careful about adding too much frozen product, because I assume if you lower the temperature of the water bath too low you are going to experience a fairly significant stabilization time as the heater will be working overtime to get back up to temperature.
I cannot guarantee that my results will match anyone else's results. I did my best to perform tests in a way that would be accurate and make sense to readers of this blog. If you think I should have done things differently, let me know!
Product: SideKIC Immersion Circulator
Manufacturer: ICA Kitchen, LLC
Available at Amazon.com