For safety, I've added deck lines running from bow to stern. I put in Yakama peddles because the originals would slide forward with just a little pressure from behind. If you stretched you legs and caught the brace with your toe while bringing your foot back, the foot brace would shift - very inconvenient when using a sea sock.
For safety, I also added an electric pump. But it doesn't remove all the water because - and this is why I gave it 9 points instead of 10 - the way the hull runs, water gets trapped in the bow and stern. Extreme edging may bring all the water to the center but then the pump can't reach it. I do like boats that have a back bulkhead that is close to the seat and slants. When tipped, all the water comes out.
But I prefer the XL's non-bulkhead bow and stern; it is so easy to load. And getting water in the boat is infrequent - almost has to be done on purpose.
I took the XL to the Gulf Island and it was a dream to paddle. We went through Portlier Pass at slack, but the winds still created large swells. I saw a sea otter floating above me. We had quartering seas from the rear and I just told myself, "Let the boat float. Let it do it's job" and I relaxed as much as possible. The XL cruised through with ease. I could swear I heard it say, "Please don't through me in the brier patch."
We paddle about 50 miles on the trip (see my Gulf Island 8 Day Kayak Trip at report at westcoastpaddler.com) and I was never sore or excessively tired.
The boat was extremely sea worthy, yet easy to roll if necessary. It's a cinch to pack but without bulkheads you need to bring float bags or trap air in empty dry bags if you go for a day paddle after unloading camping gear.
It is "Mariner Fast" but speed is overrated as a feature. If you are not paddling alone, you need to stay with your group and paddle at their speed. But you may be less fatigued because of the smooth glide.
The Mariner XL has an excellent combination of expedition-ality, grace, and speed.