Be careful when using guest blogging platforms. Even the ones that have a paid (and a pro/premium) section. See http://www.seroundtable.com/google-guest-blog-penalty-18278.html Here's Matt Cutts' info on guest posts http://www.mattcutts.com/blog/guest-blogging/ What do you think? Will you still guest post even if you only have NO FOLLOW links?
Guest Posting is still ok, just don't go with anyone that publicly lets it be shown that its a guest post. Here's how I avoid the guest post penalty: https://forums.digitalpoint.com/threads/solution-to-the-guest-post-dilemma.2706070/
The article below is somewhat relevant to nofollow links, it makes a lot of sense so I think it is worth sharing. http://moz.com/blog/how-i-learned-to-stop-worrying-and-love-the-nofollow
The article at Search Engine Roundtable linked to above by @maxauthority says, We have known for quite awhile now that Google wants natural links so the link should make sense where it is. Your guest post should be in a place that makes sense and it should offer something to the readers. The point of a guest post is to expose your business or product to a new audience to share your knowledge and present yourself as an expert in your field. If you're doing this then I don't see that you'll have any problems.