My opinions:
CJ is best of these networks
You are wrong about reporting.net, it has one and common login in reporting.net URL (but they do also provide separate logins for each advertiser).
Linkshare has terrible search function and descriptions of programs is even more terrible.
AND best of all, in cj you collect money from different advertisers to same pool but in linkshare and reporting you have to gain certain amount money separately until you see your money...
For inctance, you become affiliate for program A but manage to get only 6$ even you you made lots of work for advertising it. Then you drop the program and choose other one, Program B, gain 5$ with it drop it and so on...Now, money your cj-account has, is 11$. With LS and reporting you either try to continue unsuccesfull program until you get 20$ (which is usually minimun amount they pay) or loose you hard earned dollars.
That's why for small sites CJ could be the best option even it may seem cluttered to you...
(btw, I've never learned how to use LS, that's sure is cluttered to me)