Saveooo i'll start by saying I have expenarience with both OctaLink, and Square Taper. Personally it seems like square taper lasts a bit longer then OctaLink, due to the fact that Octalink is known for having non drive side crank problems with rotation, and damage in the inside. Just a few days ago on my 2012 Specialized Rockhopper 29ner it runs OctaLink V2, and so i could say that it lasts awhile before actually breaking down, what happened was that over time of me having to keep tighting the non drive side due to it having play, and keeps getting loose i eventually tightened it to much, and then the OCTALINK BOLT got stuck inside the bottom bracket itself, causing my crank arm so get worse over time, eventually the spindle ate through the Crank Arm itself and it did it so much to the point where the opening of the crank arm got bigger then the bolt itself, and eventually just came off which is extremly common with OctaLink V2 as said before. Now with Square Taper i haven't really had a problem with the non drive side, the whole bottom bracket itself must have either been weak, or trash... But coming from a walmart bike im not suprised, even though i paid well over 200 bucks for it, the bottom bracket became loose after a few months, and ofc i had to keep tighting it, but nothing happened to the Square Taper.... Jus t seems like it's gonna stay loose until it gets changed or aten up. BUTTT one thing i am gonna say is that Octalink is much better with Stiffness, when my OctaLink V2 was brand new with my specialized, it did it;s job perfectly, considering that i had a Shimano ES-25 BB V2 it ran very smooth compared to Square Taper which also runs smooth, but doesn't orveride OctaLink with Stiffness, i'd say for speed go with OctaLink, for normal riding and better durability stay with SquareTaper, but as of right now (2020) The best bottom bracket style would be Shimanos all new "Hollow Tech 2 BB" And i personally pick this style over, ISIS,OCTALINK,SQUARETAPER this crank comes with a Long Spindle that goes through The Bottom Bracket, and connects to the Crank Arm. This style is generally LIGHTWEIGHT, DURABLE,EFFICIENT and comes with great STIFFNESS most of all which is something we all need in our cranksets, for stability, and SPEED. but back to the point, honestly OctaLink is better then SquareTaper since it comes with more Stiffness, and it's a bit newer then square Taper, just make sure if you have OctaLink, watch over your non driveside as it;s a common problem within the system itself.