[NOTE: I'm with an SEM firm that competes with all the firms you're mentioning, so my opinion is quite possibly biased. It's quite possibly right, too.]
BidBuddy = a webified Excel spreadsheet that doesn't appear to be capable of doing anything other than helping you *administer* your PPC campaign. Keyword management systems should work in Google's opaque system, but BidBuddy was built for then-GoTo's transparent auction ($X CPC = position Y). From what I've seen as a competitor displacing them, it simply doesn't work. Why? It doesn't attempt to leverage historical impression/click/cost/revenue/margin data to build accurate data models. It can't accurately estimate the relationship between max CPC, effective CPC and resultant impressions and clicks on Google or Yahoo's new Panama system.
COBRA - Latitude's supposed proprietary keyword management technology. Show me a patent, show me proof of it being something other than [yet] another webified Excel spreadsheet that can't model or accurately estimate traffic or ROI but through pin-the-tail-on-the-donkey trial and error.
AdLearn - there's a reason none of us SEM's compete against Ad.com's search offering: when AOL bought them it wasn't for their keyword mgmt capabilties, but rather for their topline revenue and their banner network optimization. Every single time I've talked to an advertiser who was using Ad.com's PPC mgmt offering, I've heard the same story - they can hit the CPA/margin/COS/ROAS goal, but volume sucks.
If you want solutions that work, keep looking. In the interests of being fair & impartial, the SEM competitors to my firm that I *respect* for their work are:
Performics: not much technology, but they know search and if you're a big enough fish they'll put good work into the marketing/merchandising aspects of your ppc campaign
Aquantive/AveA: same as Performics. They have deep bench strength, good fin'l backing (unlike every SEM whose name starts with 'Search') and have a promising long-term corporate vision