As Boldaslove said, you really can't go wrong with either a BM or OTS. Plus, depending on the brand of tubes (or combination of brand) used; the model of speaker used; and style of guitar and/or pickup(s) used - not to mention the variation delivered by all the controls [external and internal] and bias setting - there's probably no tone that you couldn't near achieve with either model.

I think Nik might also be able to supply an alternate brand of transformer like an MM if you prefer.