The validation service returns both individual quality scores (for name, company, address, phone, email and device) and a composite lead quality score. This allowed me to set-up custom rules based on these results. The sales team has far more confidence in our leads. The Service Objects team also provided excellent support for my technical questions and the developer's section was very helpful.
The API is very straightforward but with over 50 outputs returned per lead, it can be a little overwhelming at first. It took a little more planning to integrate and make use of the additional data points.