I may be one of the few here on the moz that actually use BMR. I will probably be looked down upon by the moz community but I will give you my honest opinion.
BMR requires unique content. Yes, it only requires 150 words to get a link AND you can control the anchor text, but what is twitter? Twitter is a great example of a way that you can use a service for good or evil. I try to create every BMR article like it is a real article going to be read by an actual person (though I am aware it probably won't be).
I will be the first to admit that people abuse BMR, just like they abuse twitter. Spamming isn't a tool, it is a strategy.
All that being said, BMR is expensive, time consuming and NOT an anchor in any realistic strategy. If you are thinking more than 25% (random number I pulled from thin air) of your time and/or links are going to be spent using BMR, I wouldn't bother.
The cost is another issue. I am debating whether it is really worth the money. I like using the service along side other more "white hat" techniques but it really can be expensive both in time and in money.
It would probably take you 30min to an hour to write 5 BMR posts. Sure you can control the anchor text and you could even get a high PR from the links, but you would probably be better off spending that time getting a guest post. You still control the anchor (in most cases) and you can even control the PR (BMR randomly assigns you). PLUS if you are guest posting you are getting traffic from it and people are actually seeing your stuff. 5 BMR posts would be 750 words, that could also just be one awesome post with links being built off your post while you sleep!
In summary (because I am ranting), I use it, but never at the cost of other link building strategies like guest posting or just lurking my competition and finding out how they got their links.
Stay away from UAW, AMR, Scrapebox Blasts, SeNukeX, Bookmarking Demon etc. They are ridiculously expensive, work only in super low competition keywords (which you could rank for faster using guest posting or manual article submissions) and nowadays they only work to strengthen link wheels (which is another hot topic of debate around the forums).
So, hopefully I didn't confuse you too badly, but if you have any questions about BMR the service itself let me know.