I haven't used those, or the Marathon XR they replaced. They have a huge reputation for longevity, but I've always wondered at what cost. Is it just weight? Or have they sacrificed anything else in order to be so hard wearing?
Apart from the weight, which to me, excluding lightweight tyres like the Supreme, doesn't seem particularly high, the cost is rolling resistance on tarmac. At least in the Marathon Mondial EVO version that I know.
As with some other long-lasting tyres there might also be a penalty in wet grip, but I have not noticed any problems with that and there is a lot of rain in winter here in South Brittany. Perhaps I am just more cautious than riders who have problems with tyre grip.
In the 2024 downloadable catalogue Schwalbe rate the characteristics of Marathon Plus (MP) and Mondial Evo version (M), both in the 50x559 size, as follows, for all the figures (except weight!), high is better:
Puncture resistance MP = 7, M = 6
Rolling resistance MP = 3.5, M = 4
Road grip MP = 4, M = 5
Off road grip MP = 2.5, M = 4
Durability MP = 6, M = 6
Weight MP = 1100g, M = 740g
The results are a bit different according to the independant bicyclerollingresistance.com site. For the Marathon Mondial EVO version they tested (37-622 Evo), puncture resistance is a bit less than Marathon Plus in the same size (108 as compared to 129), rolling resistance slightly
higher (26.7 as compared to 25.5), weight
much less (570g as compared to 900).
Subjectively, I reckon the Marathon Mondial EVO in the 55-559 size I have used most rolls slightly better than the 50-559 Marathon Plus that I have also used fairly extensively. But this might be psychological due to the better acceleration with a significantly lighter tyre. They also seem more comfortable, but that might be due to me using the 55 mm width rather than 50 mm, although due to the thickness of the puncture protection layer there is less air (cushioning) in a Marathon Plus even in the same size.
Marathon Plus always feel a bit "dead" to me, although this feels less pronounced in a wide 50x559 size. I had Marathon Plus 28x622 on a pair of visitor bikes and in that size the tyres felt really awful.
IMO Marathon Mondial scores over Marathon Plus for a mix of tarmac and moderate off-road use, while remaining not as good as a dedicated MTB tyre for 100% off-road use.
For use predominantly on tarmac, I prefer a lightweight tyre like the discontinued Marathon Supreme (there are similar tyres still available in 26" in the Continental range).
If puncture protection is the absolute priority, in the 26" size on tarmac I reckon Marathon Plus is the way to go, at the expensive of mediocre rolling resistance and more weight than something like the Supreme or even the ordinary Marathon.