I currently travel with a Surface Pro along with either a Touch Cover or Power Cover depending on flight length. I also use it as a tablet at home with no cover. It's heavy for a tablet, but I don't mind all that much (usually used sitting in bed). That said, the only reason I went to the Surface Pro (atcually to an Asus T100 then to a Surface Pro) was because I was tired of traveling with an Android tablet AND a 12" Ultrabook. Now the Surface Pro is the only device I need for travel, and I overcome its battery shortcomings with the Power Cover for long flights. I would have stuck with the Asus T100 (no complaints other than cheap build quality) had the $400 Surface Pro deals not started appearing. I have no complaints about screen size, even when editing Powerpoint slides or light Excel/Word editing.
If I were looking for a new laptop (and weren't quite such a cheapskate), a $799 Surface Pro 3 would likely be right in my crosshairs. I really like only having to travel with one device, and this new Surface Pro 3 looks like a very solid laptop that can be used as a tablet as well. Now, the large size might have me picking up something like a Dell Venue 8 Pro for home use, but the Surface Pro 3 looks perfect for business travel. Even if it were exactly as designed but still a 10.6" screen, I'd still consider it near-perfect for business travel and likely an even better tablet than it is at 12".