Oh Dear !
There is not a lot of difference between Parking Companies, however mine are at Namedrive as people were having problems with UK traffic from certain Blueyonder customers a while back and all traffic from China was blocked (last time I checked) with Sedo.
The difference is really around whether your names have natural type-in traffic or backlinks that generate traffic, or whether you need a listing in search engine to get traffic.
I have got a few OK'ish name that generated nothing on traditional parking but now get $1 to $2 a month on Adsense, totally reliant on getting indexed in the three main search engines Google, Yahoo, MSN (or Live) or whatever they call it this week.
Good and OK'ish generics I think will always do better on Adsense, those names that rely on 'Type-in' and probably most TMs are best off parked, although hyphenated names even TMs do better on Adsense.
Hope that helps - there is no easy answer to 'simple moniterisation' as I call it, it take 5 mins to setup name with a Parking Co. about 30 minutes if you use Whypark (for Adsense) by the time you setup all the Adsense code, site verification codes & analytics settings (worth doing cos the the stats are excellent). If you choose to host yourself then using XsitePro which automatically creates the Adsense code for you, I would highly recommend, but is more time consuming, but you can link in syndicated articles that will get your site indexed, even if the main body of text is a load of C**P.
After that you are into serious site development, decide whether you are domainer or developer and tune your skills accordingly.
Best Regards
JohnP