Hands down tandem axle.
(and tho I noticed you said to disregard price, I think winnebagos are greatly overpriced- jmo, please be gentle with your venom on me for it).
I also agree that your first wont be your last but I don't necessarily agree that you should go bigger with your first TT. There can be a learning process and I think its important to get exactly what you want at the time of purchase. Its hard to predict what you will want to change. Personally I had to grow into the TT that we currently have- it would never have been a good one for us as a first RV.