I have an icotec 320 and have used it 1/2 dozen times. I am new to calling and haven't called anything in yet. So take what I say with a grain of salt. It seems the slightest touch of a key on the remote will start the caller if it is turned on. That can be good, I can use the remote with fairly heavy gloves which has been done this winter. On the down side, I have the mistake a couple of times of bumping the remote shortly after turning the caller on but before I was back to my sitting position. Carrying the remote in a pocket doesn't work well for me because the remote is bumped so easily.
Ive never hunted with any other caller to compare with mine but the same call used over and over doesn't sound natural to me. It seems to me that the call of say a rabbit should vary if it goes on for a length of time. Of course the call doesn't go on for a long period of time because breaks are built into the calling. However the call goes on for the same length of time, has a break in the same place every time also. Again that doesn't sound natural to me. Just because it doesn't sound right to me doesn't mean that a coyote hears it the same way I do. But, it has bothered me enough that I am now using mouth calls and leaving the e-caller home. Realize that is a big step for me because Iam not sure I am that great with hand calls. Iam sure I will use the e-caller in the future but I may call with mouth call along with it.
I met a coyote caller at a sporting goods store here in Michigan and we got to talking. He had been getting quite a few coyotes, by Michigan standards anyway. He had been using an e-caller and had 1 successful set in 20. He said that when he switched to using mouth calls his success went to 1 in 6 sets.
The other issue is the sound itself. Ive only heard cottontail distress a few times in my life, but their real sounds seemed much sharper (for lack of a better word) than the call the e-caller makes.
I don't know if what Ive been saying is true of only my caller or if they all tend to be that way.
Above aside, my caller works and Iam sure I will use it along with my mouth calls for years to come. About the time I call in my first coyote, my opinion will be subject to change.