I like that it can run in background without being too intrusive with the system, but also not so much as to slow down your computer. It's easy enough to get started using (there are some good tutorials online), but you really have to know what you're doing if you want optimal performance out of the program. If you don't understand how to use this properly then you will probably just end up wasting time trying to figure things out yourself. There is nothing in particular about One True Error that I dislike - everything seems very well thought-out. This is an excellent tool and should be considered by anyone who wants to ensure their code is free from bugs. The only benefit I've seen realized thus far has been the ability to identify which functions within my application contain errors.