I have used Blacklane twice now. The first time in Hong Kong, to get from the airport to Kowloon, and the second time in Helsinki to get from the city to the airport.
The first trip from HKIA was exceptional. It was quite expensive, but used an online offer which gave me 40% off my first ride. The driver was very professional, and the vehicle (a Mercedes Benz S class) was perfect.
The second time (on Boxing day), was completely the opposite. I booked a business class transportation (supposed to be a Mercedes Benz E class), to be collected at 8.15am. I received a message at 7.22am, advised me who my driver was, and then at 7.23 received a message that my driver had arrived. I quickly finished packing and headed downstairs, but the driver was not there. Imagine my surprise when the driver showed up at 8.10am in a 20 seat minibus. My bags were just thrown onto one of the empty seats, and off we went to the airport. Now had I wanted the public transport experience, I would have paid 5 euro to catch the tram and train to the airport, as I had done to get to the hotel. This was not what I was expecting for 60 euro!. To make matters worse, there were 2 taxis waiting at the front of the hotel, one was a Mercedes, and the other a Volvo - both much nicer vehicles than the minibus!
I have since written to Blacklane to complain about the trip, and they have offered me a 50euro voucher or my next trip, so at least the customer service follow through was ok.
As an aside, I have used another company in Europe (Basel this time), and in this case, the driver showed up 20minutes late, and in shorts and a t-shirt!. The similarity between Blacklane and this company was that both companies utilize local contractors, so the quality of the service can vary.