Solid vangs
Well, even if you use a solid vang you can still rig a preventer, so that would not keep me from enjoying all of the real benefits. For Ericsons-it is true that they can interfere with the mid hatch opening, but the solution is to reverse the hinge so it opens facing aft. This is much better when sailing as it reduces the spray which might enter the cabin....
The bennies truly outshine the 1 or 2 minor negatives-true boom support, more precise twist control, simplification of deck hardware, fewer lines and blocks, etc....
Back to a topping lift, an easy trick for the smaller E-boats is a very short line attached to the backstay a foot or so above the boom height, with a shackle on the end to afix to the end of the boom. This way you don't have line flapping around all along the leech of the mainsail, and it is short enough that you can just let it hang after you have removed it from the sail (once it is hoisted). The downside of this is that you can't use it when reefing (but you should not need one if you reef correctly)-it is just to support the boom when you are not sailing...
Enjoy!
S