We have 126" Keen Evolution. I just looked. I thought it was 124", but it's 126"
It costs, but the ease of cutting just about anything other than metal is fantastic. We just did a bunch of 114" banners and some 96" banners. 16 all total. Done within minutes. We have an order coming up in a few weeks where we'll be printing 75 or 80 5' x 10' 2-sided Cor-X to be cut down to 30" x 30". It will take maybe 4 or 5 hours to cut some 600 units to size. I'm not sure how the Saber system works, but we've never looked back on getting ours. If you only do 5 or 6 things longer than 80" a year, then go with the shorter one, but preparing yourself for the future is a goal you should consider.
We do a lot of 18" x 24" Cor-X signs. We do them 10 up, flip them and do the second side and cut 'em down in about a minute a 4 x 8. With so much substrates coming through at 8' and 10' it seems like a no brained to go big. If you've been fiddling around and making things work on a smaller scale, think about the logistics of have one station set up to do ANYTHING.
If it's the money, you can always find a little more cash to do it right. However, go small and find out you should've gone bigger, now it is too late.