This may be controversial since they are so hyped on this forum, but I regret spending the $$$ on my Arrundel sideloader cages. My 'otherside' cage was fine, but my sideloader (on the seat tube) ejected a bottle on my very first ride after 3 miles. I thought maybe the product was defective, since the cage on my downtube is just fine, so I sent it in for an exchange, and the exchange ejects bottles just as badly.
I've corrected the problem by affixing some rubber "grippers" on each side of the opening which has resulted in the cage being 100% ejection-free for over 1,000 miles, but I feel a bit duped having to bodge such an expensive piece of kit.