BI, we've carried a full set with us for 7 years now. Eventually, the
cushions will break down and crack where there is heavy foot traffic, but for us this was after 6 years continuous use, all of that in
Caribbean conditions (intense U/V & heat) or N European
weather (cold, wet). We've now flipped the
cushions over, hoping to get another few years out of them; they still look presentable and are very functional.
I thought we'd be unhappy with them at sea; the 'slipping off' thing worried me, as did the possibility of them being slippery to stand on/work from. Neither has proven to be the case. First, a good fit helps; you are sent patterns designed to fit your
cockpit, which you verify or alter (even slight changes can make a fit difference) before they are constructed. In hot climates and sun, they will swell ('inflate') a small amount, which also tends to give a good fit. (In
winter, you'll see little gaps between them appear). I don't find them slippery to stand on because, when doing so, one depresses the cushion, forming little trenches.
The real issue for me is whether the cushion slips on the cockpit seat. This can happen under certain conditions but we find that, when WHOOSH is heeling substantially and moving around a bit (what's needed to 'unseat' a cushion), it's not uncommon for a bit of
salt water to end up in the cockpit, perhaps just a tiny trickle from a splash on the coaming. Once the underside of a cushion becomes wet, they stay put. We had a heck of a Biscay crossing this past season and got pounded for 3 days, with lots of abrupt hits by square waves. Not once did a cushion slide. If you wished, you could just toss a bit of
water under the ones lining the port and starboard sides of the cockpit.
There are two vendors who make these and their products appeared to us to be identical in features and
price. Which one exhibits at your nearest
boat show, offering
boat show pricing, may be your better choice.
Jack