I’ve been using the Line 6 Helix for about two and half years and I’m so impressed and happy with the versatility and sounds in the unit. The Helix has built in amps and effects and unlike the Kemper you cannot profile your own amps in, initially I was put off by this, but the Helix has 72 built in, why would I ever need to use that many? After playing through them all, I settled on about five different ones, not because the others were bad, just because they suited my needs. You can also pair up your own amp and cabs, change the emulated microphone and placement whilst being able to change really in depth stuff like the amp biassing, so you can fine tune any amp to suit your needs.
The Helix has nearly 200 effects built in, so you can find anything you want as well as frequent updates so there are constantly added new features. The Helix also has plenty of inputs and outputs so you can make your setup suit your personal needs, for example I have an extra synth run through the Helix so I can blend it with my guitar signal.
I honestly believe the Helix is the best guitar product I’ve ever bought and the fact I’ve used it for so long is testament to that! (My musician friends jokes how quickly I buy and sell my gear).