* Reliable pickup in about 10 minutes by hitting a button on your phone or a text with your address -- no need to call or tell someone the address. If you've ever had the experience of waiting 30-45 minutes for a cab to ride a couple miles, or maybe the phone line is just busy, you'll know why reliability is important.

* Clean car with friendly and helpful driver (who you can rate). Seems minor, but it opens up possibilities. If you're on a date or business meeting, and for whatever reason need a ride somewhere (e.g. after drinking), uber will enhance the experience rather than cheapening it.

* No money changes hands (taken from your card on file at uber, including tip). Receipt with lots of details (including your route on a map) is emailed immediately.

* I'm pretty sure it's cheaper if you are above $15 fare, or about the same maybe.

I don't have any affiliation with uber, but I have had a great experience so far (only twice, once for me and once for someone else). I plan to use it a little more often.

I guess, in retrospect, I could probably have been happy using cabs more instead; but they just always seemed more awkward, unreliable, and just less pleasant. If I can get this for the same price, why not?

Cabs might still be better for areas where they are easy to get and you're going short distances, e.g. Manhattan or Las Vegas.

Uber is a taxi/livery service that magically uses technology to do things that shuttle/livery services in major cities have already been doing for years.

The difference is that: (1) Uber is a startup, (2) Uber is backed by YC, (3) Uber lets anyone be a driver, (3) Uber ignores the laws and/or regulations in the cities that it operates until it gets caught and threatened with major lawsuits/fines, and (4) Uber promises 10-minute pickups (sub-hourly timeframes between reservations and pickup are the defining line between livery services and cab services in many cities).