What's the best place for selling / buying text links?

I've used textlinkbrokers.com but they seem to have very few advertisers and most inventory goes unsold.

I've used text-link-ads.com but their customer service is appaling. They have a lot of advertisers but their system is screwed up, keeps flagging that links seem to be broken when they're not and end up wasting a lot of my time proving to them that I am doing what I said I'd be doing! Arrgghh! (I use their manual system as I don't want their script on my sites).

There's the option of Digital Point, but there are so many crap links being sold there it would be difficult to get my quality sites - not dropped domains, not fake page rank, not nofollow, not sitewide etc - to stand out.

My ideal situation is to do deals where the payment is monthly via Paypal subscription or yearly in advance (slightly cheaper). The sites are really top notch sites with material written by experts, links only to relevant destinations, very limited outgoing links and top Google rankings in tech, webmaster, teaching, software and other industries.

Despite the limited under the radar advertising I accept with no more than 1-2 links to the page, I've got about $5,000 pm of inventory for text links. Any suggestions?