My SP3 has replaced just about every thing in my house, except for my Phone, and my SurfaceRT. The only reason I keep the SurfaceRT around is for surfing "questionable" websites and such, because it isn't susceptible to malware, viruses.
For me, it is the perfect size for a tablet, and the weight... It weights about the same as my SurfaceRT when you hold them in each hand. I'm using the pen a lot more instead of the trackpad on the keyboard, and for handwriting recognition (once I trained it to know my handwriting).
P.S.
I know some are going to ask, "How did you train it for your handwriting?"
Control Panel, Language, (your installed language) Options, "Personalize handwriting recognition"
Then you have a choice of "Target specific recognition errors" or "Teach the recognizer your handwriting style". Do the "Teach..." first, it's 50 sentence's you have write out, submit to MS when done, then "Target..." again submit to MS when done.
The only problem I kept running into, was the program would loose focus when I shifted my hand around. You just need to tap on the program (not in the writing area) and then start writing again. I found moving the program to the bottom of the screen helped minimize loosing focus.