Opinions, everyone has them. Happy to share mine but you get what you pay for.
I like a single loop at the end with a deep-bury McDonald Brummel splice. There can downsides, the primary being a way to attach/store the winch line when not in use. Hooks, Flatlinks, Sidewinder, etc provide a way to store line on the spool with enough tension against the fairlead to keep tidy line dressing. This is harder with a simple loop and often results in users stretching them across their bumpers to a recovery point and attaching them with a SPBS or soft shackle. This can leave the line exposed to abrasion, debris and UV. Mostly mitigated with some of the newer fair-leads on the market, loop-guard type setups, or a large button/overhand variant knots setup to to allow tension. I find myself winching a great deal, between classes, I4WDTA projects, the UORRT and my personal adventures, winch use is often weekly... I can't really say I've run into many (or any) occasions where I wished I did not have a Flatlink or similar when present on the end of my rope, thus I've not gone as far as to remove them yet. BUT, I've also never had an end link fail and become a mass moving quickly through the air. As I swap out ropes on my vehicles (I've got 600' of 7/16" in my garage that
@Paul R and I need to build into winch ropes), I'll likely go with a single spliced loop and be done with it.
At that same time, I'll drastically reduce my line lengths and convert older synthetic ropes into extensions. Much more utility out of a shorter rope for most scenario's AND you get your winch operating in it's optimal working range (layer 1, etc) more easily. If I need more distance, simply connect one of the winch line extensions. Carrying a winch line extension, two pulley blocks and soft shackles also makes it very easy to get 4:1 and various other rigging effects. Many winches still come with 100' of line, it's not a
bad idea to take that brand new line and cutoff ~35' to make an extension.
Re: Using a loop to loop knot to incorporate a soft shackle into the system as
@RockChucker has setup. You will likely encounter
some strength loss, I'm seeing anywhere~5% being listed and that is on fishing sites so not completely fair to compare, I've not tested. That is pretty small loss and should be well under the MTS and subsequent WLL of both the synthetic winch rope and the soft shackle for any proper recovery resistance you are attempting to overcome. My bigger personal concern is your changing the way a soft shackle works, particularly the variant of soft shackles I prefer which tighten the noose of the soft shackle adjacent to the knot when loaded, making it very impossible to slip out event of you have some funky motion and dynamics (tight/loose/tight action) happening which is common when winching yourself with some drivetrain assistance or when winching someone else that may be assisting with their drivetrain. With the soft-shackle knot inserted through the winch lines loop, it's undoubtedly secure when the line is reasonably tensioned but if tension drops, it
could slack enough to drop or pull the knot out. Admittedly very unlikely but it as doesn't provide any additional utility to the line, I'd recommend best practice be just using the loop and soft shackle sans loop to loop.