The electric is higher performance but both can be very powerful and you won't be at a level for it to matter for a while.

As far as a starting point, most old timers that started more than 5 years ago (not really very long ago) started with fuel helos and the most common was the .46 or .50 size, Back in the early 90's the .30 Kyosho was a popular starting helo, if you were back in the 80's it may have even been a .60. The point is you start where you have a comfort level and money to pay for a dork or two. The bigger the helo the easier to learn on. If it was me I would say start with a 600ESP though the new HK600GT is cheap but it is also unproven at this point.