We are definitely going to Ronda - wonder if also going to Arcos would be sufficiently interesting to deal with arranging bus transport and hotel. I've read the Arcos OR Ronda threads which have me leaning against Arcos but am still open.
What may tip it is if the bus route from Arcos to Ronda compared to Seville Ronda would be worth the additional organizational time and effort.
Greg, I haven't visited Arcos so can't really say. For the folks who've seen both, it might be helpful to know how many nights you're spending in Andalucía, and where.
Still open on nights at this point - I've roughed out 3-5 nights Seville, depending on whether we do 1-2 nights in Cordoba or day trip out of Seville, 2 in Ronda, 3 in Granada, But I don't have any constraints that would keep me from adding 1 or 2 in Arcos. I'm giving Gibralter, Jerez, Tarifa, Nerja a pass this time. On to Barcelona after - October time frame if it makes a difference.
I like both places, but I don't see Arcos as a place to spend more than a few hours. Ronda is good for a full day. If you were driving the white towns, then Arcos is worth a visit, but not worth trying to arrange special transportation to reach.
I like Ronda a lot. It has some small, quirky, fun museums (Bandolero, Wine), a beautiful bullring with a fine museum, and great tapas at Bodega San Francisco (a fave with locals) just outside the city walls opposite the Almocabar Gate.
I had a lovely 1/2 day in Arcos and felt that was enough. You can day trip from Sevilla - take the train to Jerez, then the bus to Arcos. It's not as much hassle as it sounds. If you can, combine it with a half day in Jerez. Try to see the noon horse show at the Royal Equestrian School and tour a sherry bodega - Tio Pepe's the most fun.
