Ok generally < so not to miss any questions
The links you describe to some extent could be considered manipulated, unless they were sites previously and have since been redirected - which is perfectly valid. However, if they have always been redirects then they are unlikely to have gained anything from those links - In my experience if someone links to a page which is redirected since existence (and google generally knows this thanks to its vast database) then it is unlikely to pass juice - but as i said if it was say a blog post on another site but the site has since moved it will carry some juice.
If you want to investigate that further nip to http://archive.org/web/web.php and enter the url which is being redirected - go back into its history (across the top) and see if a page exists there or not.
So to your main question, are commentluv links worth it. Basically it's hard to tell whether they or any other comment system offering a similar function are worth it. As with many website comments in general the links maybe set to no-follow and so not worth anything to search engines, but thats not to mean they are totally worthless - people still see and click them.
And finally, my advice is never to just look for one type of link (such as one from commentluv comments) - it's the same with any kind of link, if you manipulate a search engine by biasing towards something hugely their worth to you will diminish and your time wasted.
always look at the bigger picture.