Color me old-fashioned, but I think this sounds horrible. The noise is annoyingly like a high-pitched screech. Grating on the ears.
Then again, F1 cars have terrible sound as well. Too high rev to have a nice sound.
edit: I find it interesting that they have a Senna and a Prost. Coincidence?
edit2: their top speeds are apparently also over 140km/h lower than F1 (225km/h vs. ~360km/h). I wonder why they decided to limit the cars to that and if it's ever getting raised?
It'll only get raised with additional battery technology, I think. Around a normal track, where an F1 car will get up to that speed, it will use about 1.7kg of fuel per lap, and this corresponds roughly to about 8kWh per lap, taking thermal efficiency into account.
Formula E cars have about 200kg of batteries (a Tesla has >500kg), and these provide about 28kWh - which would run out a little after 3 laps, or perhaps less than that if the incredibly high rate of discharge caused it to catch fire. You couldn't feasibly add too much more battery capacity without weighing the car down too much.
You can get an appreciable fraction of the speed of an F1 car with a fraction of the power, and the difference is even less noticeable if you're on a street circuit; for example around Monaco an F1 car will use only 1.2kg fuel, with a much higher drag aero package.
The Formula E driver lineup is a bit embarrassing, in that almost exactly half of the drivers are failed or retired F1 drivers.
Also, F1 drivers since the turbos returned are much lower pitched, since they rev only up to I think 12000rpm now - you might be surprised!
Bruno Senna is Ayrton's nephew. Nicolas Prost is Alain Prost's son (and Alain is visible in some of the shots cheering on his son from the garage). There are a number of other close ties to F1 in both the car hardware and technology and many of the drivers.
Most of the limits on the cars are due to battery technology.
Then again, F1 cars have terrible sound as well. Too high rev to have a nice sound.
edit: I find it interesting that they have a Senna and a Prost. Coincidence?
edit2: their top speeds are apparently also over 140km/h lower than F1 (225km/h vs. ~360km/h). I wonder why they decided to limit the cars to that and if it's ever getting raised?