I actually prefer Apple Maps in the UK because the directions have so far never let me down (since I started using it in iOS 7, it was indeed rubbish in iOS6).
The funny thing is what I like about it is Apple use the correct colours (i.e. following the standard most UK maps follow) for roads. Motorways blue, primary routes green.
It's odd that Google had it correct, but then switched to US colors for UK maps when they updated it. When Apple Maps in iOS 6 launched that was one of the things I hated, but they fixed their colours while Google went in the other direction.
One thing I do like about Google is they use the correct British symbols for Rail station, Tube station, Metro, etc whereas Apple uses the generic icons in circles. Hopefully they won't remove that feature.
On the desktop I prefer the classic Google maps to the new Google maps.
Also recently Apple have been processing my corrections within 3 days so I'm starting to gain more confidence in them.
I was told by an Uber driver that Google is a major investor in the company. Although it's odd in that case that each Uber drive is given an iPhone by the company. Uber is also supporting Apple Pay in-app.
I do question the company's morals in some cities but in London they operate entirely within the law, although it's worth remembering that for short journeys it's usually worth paying more through a licensed cab (e.g. through apps like Hailo or Get Taxi) because they can use bus lanes (very beneficial in London traffic) and know the area better due to 'The Knowledge' (a detailed exam about the streets of London).
I will say UberX (Uber's cheapest cars) is excellent value if you need to get from Central London to Heathrow Airport. Although the tube trains will only cost about £4, the Express train is a ridiculous £21 per person but UberX is £37 to most destinations so cheaper if two or more are travelling and of course the benefits of door to door transport. A normal taxi will cost anywhere between £60 and £100 for the same journey (depending on traffic, time of day, etc).
