I recently visited Aslanhane Mosque (in Turkish, Arslanhane Camisi) in Ankara as I was already in the city for the day due to a flight connection. This Seljuk mosque, built in 1290 CE, seems to be a lot smaller and less interesting than the other locations of this WHS. Thus, I wouldn't recommend it as a stop to anyone besides WHS travelers. I have seen a lot of Seljuk mosques/madrasahs, of comparable age, that are more stunning and visually intriguing during my time in Turkey (the Çifte Minareli Madrasah in Erzurum, built 1265 CE, if you want a rec)! However, what makes these hypostyle mosques interesting are the wooden beams inside, thought to have originated from the Mongol invasions half a century prior, according to UNESCO. When you arrive, there is a small plaque explaining the mosque's significance in Turkish only. In summary, Aslanhane mosque is near the historical area of Ankara, and if you are already visiting those sites, it is worth a short detour. However, I don't think I would recommend it for anyone farther away.