A few random thoughts that I've shared with others on the relative merits of each place. Some guys agree, some don't as each place has their adherants.
I've long been a fan of SL, where I've stayed about 10 times. I also like Amistad, where I've stayed probably 5 times, including the penthouses. Here is my take on both.
Sportmens' rooms are all over the place. Some of the older rooms are not at all attractive to me. I've stayed in Amor, which I didn't like at all. It was small, cramped and difficult to make myself comfortable in. OTOH, another old wing room, Felicidad, is very comfortable. I've stayed there a couple of times and been happy with it. I've stayed in the clubhouse twice and not really cared for the rooms, which are a bit long in the tooth. However, the clubhouse living room is a very nice place for a private party.
Most of my stays have been in the new wing, with Vista del Sol being my most frequent. The bed is very comfortable, the room is good sized, there is a table where I can put my computer and work for a while if need be. The bathroom has plenty of shelf space and works well. The water pressure in SL is always very good and maid service is excellent. The furnishings in the new wing are modern and attractive. IMO, the noise level for the rooms in the new wing, at least the upstairs rooms, is negligible. OTOH, having stayed in Ilusion (the closest room to the bar in the new wing), and El Rey (across the hall from Ilusion), I can attest that the noise from the bar can be a problem. However, the SL bar noise has never woken me up. It is my experience that most of the rooms in the new wing, and in the mansion, are every bit as tranquil as the Amistad.
The mansion is another animal altogether. I already have Leopardo booked for Labor Day and Halloween! I like the mansion bar and always get to meet a few great new there guys each trip.
Of course, there are many other factors that make a great hotel. It has become my habit to check in to SL, get to my room, do a minimal amount of unpacking and then hit the bar. Once I get there and order a drink, I feel as if I am in another world. I immediately lose the frown and begin to mellow out and feel good. I am greeted by a great staff, person after person, all of whom seem genuinely happy to see me and wish for me to have a great stay. Then, inevitably, I run into half a dozen familiar faces, all of whom are just as pleased as me to be at SL.
No doubt, Amistad guests are invited into the mix also. But staying at SL means that I can go back and forth to my room, or wherever, without having to pay my bill. It's nice to have all of your stuff there at the epicenter. I get frequent room service when my favorita is in tow. Also, the SL staff treat her with warmth and respect.
One of my 'things' is that I like to bring a few of my own alcoholic concoctions, prepare them in my room, and drink them in the bar. That has never been a problem and would be impossible if I were staying at Amistad. I also like the fact that I can come and go from the bar/restaurant without having to worry about paying the tab. I usually just settle up at the end of the night (or not if I've been detained elsewhere).
On those occasions when I tend to drink a bit too much, I need only walk a few feet to my room. On many occasions after the bar has closed, several partygoers follow me to the room and the party continues. When I drag my ass out of bed, I slip on a pair of shorts, a t-shirt and some flip flops, and head to breakfast. The free breakfast, admittedly, is not sufficient for me, although I do enjoy the fruit and OJ. Because SL seems to be the gathering place, I usually am able to connect with someone who is going on a MP tour, or just heading out and wants some company. So, I walk another few feet to shower and change. There is a big advantage, I believe, to staying just a hallway away from party central.
I've always liked being able to keep an eye on the ladies congregating at SL. Having a room close by gives a monger the advantage of wooing the lady in the bar, and still having a hard on when you get to the room. I also believe that the ladies are somewhat more incentivized to provide better service to SL residents, given it is where they 'practice.'
Amistad has the advantage of a free breakfast, and free laundry. From what I hear, it is now pretty much dust free. However, the times I stayed there, it was dusty and had its own noise problems. Also, I recall the water pressure being iffy at times. That might have changed with recent renovations. I never had a problem with the ecotourists although I always suspected that they were a bit judgmental.
All in all, I prefer SL. It is somewhat more expensive, but is more in the line of a full service establishment. They treat me extremely well, and I always have a good time there. As I said above, once I arrive, my cares and worries dissipate. Amistad, although a very nice place, doesn't give me that same feeling. When I arrive at Amistad, I unpack so I can get my ass over to the Sportmens.

Sportsmens, for me, embodies
Pura Vida, and allows me to be in the thick of it. Or not, because if I need some alone time, or a nap, I've but a few feet to travel.
Ciaociao