I should be more specific: this applied mostly to Grab, an Uber competitor (the South East Asian Lyft if you will), in its early days before it implemented its own surge pricing (which is invisible - the price changes upwards, but is quoted upfront after you enter your destination).

Today, both Uber and Grab have relatively short dispatch times (usually < 1-2 minutes where I live) at all times of the day and night.

The interesting phenomenon is that both are running incentive campaigns and depending on which one has the better incentives, the other one will end up with dispatch times over 10 minutes. Like many customers, I run both apps and pick whichever is the flavour of the week based on dispatch time. I have a very slight preference for Grab since they quote the price upfront, but generally, taking UberX after a Grab quote, it comes to the same number or within 5% either way.

Talking to drivers (I take Grab/Uber over 10x a week), I've noticed:

- virtually all (one exception in the last 4 months) drive for both, and have a phone for each (Grab does not have an iOS app, apparently);

- virtually all drivers have done it for less than 6 months, lending credence to the "fast food joint" theory of Uber driving (that it provides temp unskilled jobs with no long term prospects like fast food joints in the US);

- maybe 80% of drivers are part timers, often unskilled workers (e.g. shop staff, construction) who are moonlighting, often because they have a lot of kids (highest was 8) and their wage is not amazing;

- taxi drivers tell me virtually all bookings are now from either of the apps; one said he did only one physical street flag in the last 6 months! I anecdotally knew this to be the case for me, as even when the taxi queue is free I still book my car via the apps, so I don't have to pay in cash and because dispatch times are so quick;

- some of the incentives seemed pretty good: if you made $150 in one day (the average trip being around $6-8) you got a whopping $23 extra per trip!

Taxis in Singapore get substantial discounts both on car rental and gas ($0.70/l diesel for taxis vs $2/l petrol for everybody else) so the economics are funny; Singapore is one of the few countries where taxis are competitive with UberX. During surge hours, I take taxis on Grab since the rate does not seem to be surged unlike Uber, and there's always plenty around.

This is not true of all other countries I've used Uber in. For example, in Sydney, in the last 2 years UberX has been about half taxi equivalent fares; in Paris, Uber Black (UberX is now famously illegal) is slightly cheaper than taxis but you get a really nice car and a much friendlier driver.

Emotional anecdote: I had an older Malay driver who struggled a little bit with English and upon driving past Little India, pointed at his old school (he now lives a good half hour away as the area has massively gentrified). He said he got in with a bad crowd at school and spent many years in jail due to gang activities, but he climbed back out of it, got a job, married and had two kids. He drove Uber/Grab in part because the money was exceptionally good compared to his other options as an ex-con, in part because it was a way to have a car in Singapore where the permit for 10 years of ownership costs upwards of $100,000, the apps income offsetting the rental cost for the day. He wanted a car because his kids were proud and happy when he drove them to school instead of having to take public transport. He said this practically with tears in his eyes as if it was the most important thing in the world to him.