Small blue: I've asked my partner to explain how he compares them and he can describe two things:

1) The sloe vodka has more of an almondy flavour, which is possibly coming from the stone of the sloe. Maybe the vodka is better at extracting this?

2) Whilst the alcohol content is the same, he feels you can taste the alcohol itself *less* in the sloe vodka than in the sloe gin, and the other flavours a bit more.

Of course, this is all based the one (and only) time we've made (and tasted) sloe gin and sloe vodka. The sloes were of the same harvest. The gin was Gordons London and the vodka was probably something very cheap from the local co-op (as it was a last minute thing).

Again, we found both the gin and vodka good - just the unexpected surprise that everyone (but me) liked the sloe vodka even more.