I second VibraCart Pro - it’s a very nice and future proof product.
Ecwid has good integration with RapidWeaver too, but only if you add EcwidPro ($70, Axyn Technology) into the mix. Ecwid’s own (free) plugin is rather limited in functionality.
Two things to keep in mind using Ecwid: the prices have recently gone up quite a bit, making them slightly too expensive for what you get IMHO. Also, their SEO is horrible unless you use their own store builder, so you’re going to have to invest a lot of time into getting your SEO back on track.