Studs are far easier to fit wheels to than bolts, especially with loose spacers. However, unless you intend to be taking your wheels off frequently you would be better spending the £50 odd pounds on something more enjoyable.
As for length of studs or bolts. The function of either fastner is to be in tension and create sufficient static friction at the hub face between the wheel and hub that nothing moves. In this the length plays no role as there should be no radial movement between any part. If you have movement, your wheel is loose and you are going to have issues regardless of bolt or stud length. It is equally important that you do use the proper torque, or more to the point not excessive torque when fitting wheels and not the internet "I do them FT" as over tightened bolts / nuts frequently lead to cyclic fatigue failures on wheel fixings.
