This unit is incredible for the price. I remember most modelling pedals being cheap and beginner level about a decade ago but it's not the case these days. The GX is very well built, heavier than I expected. Every switch is fully programmable and customizable, per patch. Can also send MIDI CCs per switch, so I've mapped some switches in Ableton Live for scene scrolling and launching. The display is great but the unit can be used without heavily relying on the touch screen and instead by using buttons and encoders. The rotary encoders feel great, are not cheap, are indented and 'click in'. The four rotaries below the display can be mapped to any parameter within the patch for quick access. Very logical and straightforward UI, doesn't take long to learn. The blocks (hexagons) are color coded by category. No latency to speak of when playing and switching patches. A separately sold Bluetooth module can be purchased for editing of patches on an iPad or phone, so you don't have to crouch constantly. I've literally recreated my own rig (amp, stompboxes) on the GX-100 and couldn't believe how good it sounded and responded to touch, so I'm selling everything and keeping this as my main amp/effects unit. Near-infinite possibilities in patching, routing and assigns, including the expression pedal, which has good travel and sensitivity. Time based effects such as delays can be tempo synced to an incoming MIDI clock, or you can set the GX to be a master clock and send a MIDI Start/Stop from one of the switches. BPM can be set per patch also. The looper module seems to be basic because obviously Boss won't eat into its own looper market with the GX. I couldn't find a way to sync the looper to the internal or external clock or quantize the bars, so it's just a basic looper for quick ideas, with you as the reference in timing. Maybe it'll get better with an update but it's just a minor con for me.
Overall, I'm very impressed with the GX-100 and would recommend it if you're in the market for a swiss army knife of a modeller on a moderate budget.