If you liked the U4, definitely should try out the shrimps. Feels very close to the u4 68g in terms of firmness but smoother on the up/down stroke. The bump is slightly more distinct. Just wish they would offer it with lighter springs.
On the cheaper and lighter bump end, I'd recommend either Wuque/Haimu silent tactiles. Very smooth and silent but you're giving about 50% of the bump, but great for office environments and fast typing.
Nothing fancy at the moment as I haven't had time to play around with it, but VIA/VIAL config software allows for complex macros and customizations. I currently just have the bottom row for basic audio functions: back--play/stop--forward and the knob for volume. Top left button is to put my Mac to sleep if held for 1 sec, and shutdown/restart menu if held longer.