I agree with Jonathon. Overall, this is a waste of time and money, better off spending time on having the pat timer write guest posts for quality sites. Within content links are the best ones you can get.
I have paid for WSO's at Warrior to do this, most of the time the High PR dofollow blogs that are used in the services are nothing but endless pages of SPAM, since most all spammers know about these blogs and other warriors are buying these in droves.
One report had several sites that had more than 1000 comments, all kw links. From the 25 high PR links I got with that service, and were talking PR6, 5, 4 there was absolutely NO movement in SERPS.
Bottom Line
1. By the time you get to comment #100+ the link juice is so diluted that it's really worthless
2 .You run the risk of being clustered with spammers, casino, viagara, etc...
3. It is risky for money sites because it is so obviously link spam
4. Would not pass a manual inspection by G to be deemed as quality links
5. Overall, these are not the strongest links anymore, G devalued blog comments some time ago
6. Really they are only optimal now if you can find sites that have high PR on page and very few comments and post a real comment by hand.
7. Link bombs of 5000 blog comments in one day is bad these days, G is real good at penalties these days.
There is one thing about blog comments that is still positive and that is it can get you a more diverse IP link profile, but it's best to get blogs with low comment counts, no on page SPAM comments and both dofollow and nofollow links.
Hope this helps.