Hi, I am in a M/F relationship but I do play with women.
Harness wise I would recommend either the RodeoH or SpareParts series. I haven't tried the RodeoH series but I am interested in them and heard great things from couples in both F/M and F/F relationships. They range from feminine http://www.lovehoney.co.uk/product.cfm?p=28038 to masculine http://www.lovehoney.co.uk/product.cfm?p=27629 and http://www.lovehoney.co.uk/product.cfm?p=28625
There is also the TruhK http://www.lovehoney.co.uk/product.cfm?p=28168 which are designed to be used with Strapless strap ons.
They aren't adjustable so if you both want to use them and you are different sizes then you will need two.
I would also recommend the SpareParts series http://www.lovehoney.co.uk/brands/spareparts/ I have the Theo and it is the best harness I have ever used. Comfortable, adjustable in size, O-ring fits most dildos and you can swap half way through and best of all it is machine washable. There is also the Deuce which is a double penetration harness.
The harness and dildo combinations work well as they are so many variations to try. If you want more pleasure than you could try internal toys from dildos to eggs. You could (also) try clitoral and/or anal toys too. I find that the We-Vibe 3 works well here, not so much during sex as it moves around too much. The only thing is that I find harnesses more difficult to use than strapless strap ons which are almost an extension of myself and much easier to use and feel.
I have one from Tantus and one from Fun Factory. Both are extremely good quality but the Fun Factory one is much heavier which means my kegel muscles have to work much harder to keep it in place. The Feeldoe and Realdoe range by Tantus have very good reviews and I hope to try one at some point.
I hope this has helped.