I've been using a Surface Pro 4 for the past 5 years which has been great.
Its essentially a tablet that runs the full version of windows, so all your main programs and apps can run as you'd expect. Ive got mine hooked upto a monitor as a second screen along side a wireless keyboard and mouse. The great thing is, should you want portability, simply use the snap on surface pro keyboard and you've got a fully functioning laptop too. Its been a great tool, coupled with the pen as well it gives me great options for working.
Prior this, I was using the brilliant iMac but sadly as I needed the flexibility and portability, I had to jump ship to Windows as the ipad pro just didnt cut the mustard. If only Apple would stick MacOS on a tablet that wouldve been great! Anyhoos, I can highly recommend a Surface Pro Tablet to anyone interested.