Hi @R_G Old timer like me (70) hope you are staying safe (and warm) in Quebec City. I see that you have a mind that is open to other distros and don’t necessarily go with the down the mainstream ubuntu-mint path. Check out groupthink when you get five minutes spare.
Gather that you liked Win-XP but unlike you I still use it regularly for SolidWorks 3D CAD, FEA mechanical stress analysis, Gas flow; wind tunnel analysis, CAM, Professional DTP DeskTop Publishing, movie making and editing, photo editing plus RAW. The 20 year old box, built by a friend, still outperforms modern Win10 laptops, possibly because it isn’t slowed down by AV etc having never seen the web…!
Spot the difference … Jump Ship to Trisquel without any problem…
I started gnu-linux path with Dell E6420 dual boot Win10 Pro-ubuntu 16 which I don’t use hardly at all now as Trisquel is much better on a 13 year old HP G60. I do not do gaming other than occasionally Pinball on XP to test my reactions. It was such a revelation finding the FsF and Trisquel - in some ways like a modern progression of WinXP-Pro with everything so stable, fast and snappy - hey; even www too! You can hit the ground running with Trisquel coming from XP-Vista-7 being productive in first five minutes it is just that easy to use compared to ubuntu or Win10 for that matter. Simples - init…!
Okay let’s give you the short answer - efficiency or lack of - just take a look at the CPU in my pictures 28% compared to 62% for Mint. Wo Dude; check out the mint CPU History maxing out at 100% - inefficient or what… Just like Lotus pissing over American Lard years back or my super agile CCM Rotax R30i SuperMoto pissing over a bloated Harley mid corner etc etc etc…
I posted this yesterday…
So funny that Akito and my super-fan Howard reacted so predictably. Akito even said, before I proved the exact contrary, that I should be unable to watch a video with so many tabs open and other apps loaded as it would be sooooooooo slooooooooow on old hardware. Just how wrong can you get… 
I used to test power, torque and efficiency of race engines on a dynamometer back in 1969 where counting small differences was the difference between winning races and coming second. As they say - who remembers who came in second, third or forth…?
Hope I have answered your "Why do you believe Trisquel is better than Mint on that machine ?” Please do not pay that much attention to me or the “groupthink” detractors just drop Trisquel onto that old HP G60; smile as you consign Win7 to oblivion in the void - and never look back.
ps Anyone want my Dell E6420 quad core i7 dual boot Win10-ubuntu laptop-notebook…
make me an offer -
(Alloy chassis, American illuminated keyboard layout and no number pad)