iPilot - spot lock feature. Is it truly as good as it sounds

[marshgrunt]

I'm asking for feedback on the iPilot type trolling motors with the spot lock feature ... From you guys that have been using the device. What have you found to be some of its limitations?
The wife and I coastal fish quite a bit but it's mainly myself who runs the trolling motor and there are too many situations over the years where current and/or wind move us off a spot or towards an object when I'm taken off the front deck for one reason or another. It would be great to press a button and have the t-motor hold our position, be it near jetties, along the beach, out in open water over a reef, ... While spot lock sound great, is it really? What situation have you found the feature didn't perform well in. It's limitations.

I've got a 2110 Nauticstar with a 24v manual trolling motor that has sufficient power for about 99% of the situations I've encountered (pulls boat about 4 mph). Fishing grounds are big lake, vermillion bay / coast, Timbalier islands / bay to grand isle.