Which is a better backlink?

Which is a better backlink: Profile Links in a Forum or a Comment Link on a blog post?

I am undecided, they both have some good and bad parts to them. I am very new to SEO, but it would seem to me that the comment link would have a better chance of staying around longer. The reason I think that is because I have posted comments on some blogs a long time ago and they are still there. Recently I did a few of Angela's Backlinks on some forum profile links and they have been removed, and yes I waited 6+ days before I put in my links after I set-up the profile.

I think that profile links are great, but very time consuming to do and if thats all you are there for, it will eventually get found out and your profile will be erased.

I think with comments, at least the blog post that is being commented on will be archived in the blog for people to search. Therefore will at least still be a backlink.

I am looking at this for websites I am building that I will be selling within a few months and for websites I am keeping. Which type should I put more effort in to see results faster? And which one would give greater long lasting results?

Thank you,

Adam