I have multiple problems with ridesharing services:
1) They foist the risk off onto the contractors while keeping all the profit themselves. They could have been a well-run national taxi company that serviced suburbs (and would have had STAUNCH defenders), but that won't get you unicorn valuations.
2) Most of them are using VC money to subsidize the ride costs. This is fine--until they run out of money. Then the cities will be left to pick up the pieces when suddenly there aren't enough taxi drivers anymore to service the demand. Uber and Lyft actually tried to use this as leverage in Austin to get their way politically. So, the threat is not theoretical. These companies are not trying to service the customer; they are trying to become the taxi monopoly.
3) Uber/Lyft/etc. drivers often don't comply with local laws surrounding carriage services. This includes licensing and insurance but also includes simple things like "Where in the airport am I allowed to pick someone up?" I have had a not-insignificant fraction of drivers who simply don't know where they are going--especially if "surge pricing" pulled them in from an area outside their usual haunts.
4) I have a problem with Uber, specifically. It seems like it's run by a bunch of nasty, rich, party boys and their treatment of people they regard as beneath them is absolutely disgusting.
I like the fact that the ridesharing services have forced most cities to start issuing more taxi permits. I like the fact that the ridesharing services function in the suburbs where taxis won't go(mostly--I have had some misses). I like the ridesharing services when they lobby for laws attempting to break the taxi monopolies.
So, my verdict is still out.
(Edited: I can haz English. Sheesh, my grammar is starting to suck.)