I don't have personal experience, but here are some thoughts based on the specs, etc.
Icon iKeyboard 6 - Semi weighted keys. This may be an issue for you if you want to play fast, synthesizer runs. On the other hand, if you've played piano a lot, you may be more comfortable with them. Touch strips are interesting, but most people I've seen like modulation wheels and/or joysticks. The description doesn't specifically say this, but I can't imagine a semi-weighted keyboard that isn't velocity sensitive (like a piano). But there's no mention of pressure sensitivity. Both USB and MIDI connectors means that you've kept your options open for sound modules, etc. Both sustain and expression pedal inputs is a good thing.
Alesis V61 - Looks like an unweighted keyboard, which has the opposite pluses and minuses as the Icon. The description specifically states that it's velocity sensitive, has modulation wheels. Again, nothing about pressure sensitivity. It has velocity sensitive pads, too. But the connection is USB only, which excludes the use of most direct connections to sound modules. (This won't be an issue if you're only ever going to use it to control Pro Tools.) No sustain pedal input may be an issue for you.
M-Audio Keystation 61 II - Semi-weighted keyboard. Velocity sensitive, but not pressure sensitive. Has both USB and MIDI connections, keeping your options open. Pitch bend and modulation wheels. Sustain pedal input, but no expression pedal.
M-Audio Oxygen 61 MKIV - Un-weighted velocity sensitive keys. Not pressure sensitive. Has velocity sensitive trigger pads, too. Sustain pedal input, but no expression pedal. Appears to only have a USB connection.
Nektar Impact 61+ - Un-weighted velocity sensitive keys. Velocity sensitive pads. USB only interface. Sustain pedal. Pitch bend and modulation wheels.
For ME, none of them fit all my wants. I'm not picky about the keyboard weight, but would want both sustain and expression pedal inputs, MIDI and USB connections, velocity sensitive pads. All the DAW controls would be gravy since my computer has a touch sensitive monitor. But that's me. For you? What do you think is important, and what can you live without?
(One that meets most of my needs is the
Roland A-800PRO. It even has aftertouch (pressure sensitivity).
After I wrote the above, I found an interesting article at
https://www.gearank.com/guides/61-key-midi-controller