First, let me begin with full disclosure. I am Russ Jones, CTO of Angular (formerly Virante) and creator of Remove'em. I will do my best not to make this an advertisement in any way and answer the question more generally about link removal services.
"My question is, has anyone used them, and did you see any results?"
The answer here is a definite yes. We should probably distinguish between link removal tools and link removal services. There are some tools out there that assist with the link removal process (Remove'em, LinkRisk, LinkDetox, and Remove'em etc.) and other tool/service blends that perform a degree of the link removal process (Remove'em Full Service, RMoov, etc.) and finally some service-only models (LinkDelete, etc.). I will say that I am personally unfamiliar with the service-only models so I will refrain from comment on them out of ignorance, not because they couldn't very well be useful and effective.
The blended services, by and large, appear to be effective. We have researched our competitors and I assure you if they were a sham, we would have made that clear in our marketing material by now
These services tend to provide the following improvements upon DIY...
1. Existing relationships with link purveyors to accelerate link removal.
2. Outreach technology that allows them to better find contact info.
3. Existing databases of contact information tailored to this industry.
4. Knowledge of Google expectations for successful reconsideration
However, you don't need any of this to run a successful recovery, the question is just a balance of your time and money. If your lost revenue from lack of rankings, cost of time/services (ie: employees or existing SEO firm running removal campaign) are greater than the costs of these services, they are well worth your consideration.
If you have an specific questions about these services beyond their efficacy, feel free to respond here - I would be more than willing to help.