I have to agree with this. I tried (and tried and tried) to move my company's ailing VB-based CRM system to a OOTB solution, but none of the platforms I tried (Sugar, VTiger, and a few others) really did what we needed. Either too much or too little complexity and customisation with each.
In the end I gave up and spent a week designing, and then another two weeks implementing, the first version of a custom-built solution using Zend Framework (yes sorry, feel free to snarl at my framework/language choice, but it's great for quick prototyping and RAD). Obviously I've had endless feature/bug fix requests ever since, but after initially trawling the SugarCRM code it became clear that any amount of customisation on their awfully confused and verbose code would be so troublesome, and that our needs as an small business were so specific, that getting any of the other solutions into shape was going to be an entirely joyless exercise.
If they'll give you a few weeks of time to do it yourself, and you follow good coding practice, you'll end up with something far more lightweight and fit for purpose.