A quick way is just to look at PageRank. PageRank is almost directly relative to a sites backlinks. This means that if you are going up against 5 PR6's it is probably going to be really hard to compete against them without ever having to look at their backlinks.
However, if you want to go further, I would just analyze the Top 10 competitors backlinks. Be realistic yourself, can you beat them in the 4 areas really relative to SEO? I don't think you have to go any further than the top 10 in terms of analyzing. I don't see the point of analyzing the #20 site when even if you beat them and go to #19 you won't receive much traffic (if any). If you can't compete in the top 10 you may as well give up and find another keyword to target.
VAVA - Volume, Authority, Velocity, Anchor Text
Volume - How many backlinks does your competitor have? Can you beat them in how many good backlinks you can get?
Authority - Lets face it, Scrapebox and Xrumer are good tools, but at some point you're going to need more than profiles and blog comments on unrelated sites to compete against good competition. Can you do it?
Velocity - This ones is pretty easily attainable if you outsource some of your backlinking or use any form of software. I don't even really include it, but some do so it is worth mentioning. Besides, throwing out 1000 backlinks when your 5 year old competitor has been #1 for 3 years doesn't mean you're going to outrank them if they only get 10 backlinks next week.
Anchor Text - Like I said, automated software can sometimes do it, but Xrumer will often throw a bunch of images as your backlinking text / image. This means not much link juice for you for your targeted keywords. Try to find good quality backlinks where you put your keywords in as your anchor text. If your competitor has theirs spread out too far, you might be able to beat them by really targeting a few keywords.