If you pick on horse trek choose it this one! I couldn't book online but it was easily organised once in Sofia. I was picked up, my valuables were safely stored and my glasses which I foolishly left behind were returned. As an experienced rider (over 10 years) I had a 3 hour ride through changing forests with only my guide. We walked, trotted and galloped (my lovely mare had a decent trot, disunited canter and a slow, solid gallop). The tack was English and fitted well, the horses happy, friendly and absolutely bomb proof for a beginner. The ride was beautiful through changing forests and a stunning view of Sofia from the waterfall at the end.