It is slightly odd the way the Reverb one works so much better “wrong way round”, what were they thinking? Upside down doesn’t just protect it better, it puts the button in just the right place for a thumb too (which must have come as a shock to a company that makes gear shifters)
Judging by SRAM backup, reverb spares are pretty eat to get hold of anywhere, its not enough odd a reason for me to consider anything else.
You can order them anywhere but you can’t walk into many shops and buy them. I crash-damaged my i900 in the alps and it was a relief to be able to just keep on going, as even with a broken lever it could still be raised and dropped easily. I could have easily repaired it but there was no need.
Mind you KS have taken a step back here too in some ways, that’s not so simple with the Lev (though still easier than a reverb) I did an SDA round last year at Glencoe where a chap put his reverb-equipped bike on the chairlift and snapped the barb off- finds himself up the mountain with a seatpost he can’t drop. Unlucky!