There is a warmth to the driver for sure - but not something obnoxious by any stretch. The Sapphires are ported completely differently than the SSR's. BTW, the SSR's can also be ordered as sealed for use with a sub if desired.
There is a nice organic sound to the SSR's with the right components in the chain ahead of it. It's a very revealing design and very sensitive to changes in the system. They're very dynamic and clean and image as you'd expect a good monitor to.
If you're going to try something with the OW1, you'll likely have to cross it over a bit higher. The OW1, however, is closer in efficiency to the Revelator woofer where the Fountek in the SSR is padded down due to it's 95db efficiency. The OW1 is 87db.
Bryan