No such thing as “best” - depends what you’re using it for, in terms of considerations here’s where I’d place priorities:
water/weather tightness
Ease of “installation” & how quickly can be removed & re-installed (most important when discussing tonneaus that don’t provide complete access like a tri-fold)
Security/durability- soft roll-up vs a hard tri-fold vs a solid cap type w/ a legit locking mechanism
does the tonneau utilize the trucks rails (usually more waterproof & still allows using bedsides as “seats” or grab handles) vs ones that incorporate their own tracks (typically less watertight, not usually ideal to sit on or put any weight on & need to be careful about cargo smashing into the rails damaging them- upside I guess these ones are usually more low profile)
looks/aesthetics
see a lot of people recommending the bakflip type....I’ve had one previously on a GMC truck- they look cool, some of em are more durable/secure than others that use composite aluminum/plastic panels- my experiences was such: they aren’t weathertight, period. The inner rails are fragile & awkward to use for sitting, the drainage tubes don’t always drain & if/when they get clogged smell like ass (easy fix w/ some bleach/water mix or simple green & hot water- but worth mentioning), & on mine the horizontal weatherstripping in between the panels began to delaminate/disintegrate over prolonged use.
I always recommend the advantage hard hat tri-fold B/c it’s super easy to remove & install even tho tri-fold, durable, waterproof, pretty secure & w/ a locking tailgate can be made so tight you’d need a sawz-all &/or pry bar to break into (this is from first hand experience when I had to get into the bed of my then totaled GMC @ tow yard to remove tools etc from bed)