The utility isn't that bad. Most of the 'errors' things that the utility would have to make assumptions about. It flags these items so that you will look at them to ensure that they are correct.
For instance, ControlLogix only has millisecond based timers. SLC have at least two different time bases. Now when the conversion utility comes accross a value being moved into a timer preset, it flags this to ensure that the user has the correct value in the timer.
I used the converter on many projects where there wasn't time or money to rewrite the program from stratch. After some minor cleanup, the program ran fine and did what it was supposed to.
Now doing this, some of the features of ControlLogix aren't being used, mainly the ability to use tag names instead of addresses.
It realy depends on your time and budjet whether to use it or not. It isn't really that bad.