I agree with the SIG Hog Bipe. BUT...I have had the Carl Goldberg Ultimate and if you use the YS110 turning a 16X6 APC you will have a great combo especially if you use twin elevator servos in the tail for the elevators. I did this and was able to move the tank onto the CG with no added weight.

As others have mentioned, bipes need power all the way to the ground. That being said, my CG ultimate was probably one of the best flying bipes I have had. With the combo I suggested, it would take off at half throttle, cruise around all day long at half throttle and on low rates it was a big baby. Turn up the rates and send this thing into one of the most beautiful inverted flat spins you ever saw. Lomcevac's were wild once it got started and blenders were extremely violent but very easy to control. Rotation around the yaw axis was unbelieveably fast but very easy to handle.

At first I did have orientation issues with it but I added stripes on the bottom at a 45 degree angle pointing towards the nose on both wings and the horizontal stab and some lettering on the top of the top wing and it became allot easier.

Now I am currently getting started on the Wildhare Ultimate using a 50cc gas (haven't decided on which one yet) I also have a GP Super Stearman on the bench that's almost completed using a lightened G26 Zenoah. I actually have flown this combo before and it's also a good first bipe. Use the recommended OS120FS and you will need 18oz's in the nose but they supply a weight box for it. I also flew that combo and it's not bad at all.

If you are pretty good at orientation, can pretty much make a plane do whatever you want it to do safely, then I would say go for the bipe. You will never not have one again. I sold my Ultimate and spent all winter in withdrawl [] so I bought two just in case.