Teoma has some excellent features - its refine feature for example, makes it much quicker to refine your search and narrow down the relevant results than is possible with the likes of Google and other big players. It's easy, quick and intuitive. Combine this and other features with a pretty good algo and you've got the makings of an excellent search engine with heaps of promise.
Unfortunately, the index is presently quite small and what is there simply isn't updated often enough. If this were to change however, I genuinely believe Teoma could provide some stiff competition to Google and others.
I've put the proverbial money where my mouth is and use paid inclusion to Teoma. Referrals are slow but steady, with good placings on Ask and again, reasonable referrals through this.
It only takes one conversion to recover the cost of inclusion & we're well beyond that mark now.
Teoma has many things going for it and given a little effort and expansion - as we all did with Google (and apologies for mentioning them so many times in one post) - we could expect the same from Teoma. You pays yer money and you makes yer choice!