I think there is a certain type of person who likes seeing ancient institutions of learning, and if you are one of those, Winchester college will be a nice attraction to visit. Someone once described Winchester as "a little slice of Oxford which feel to earth", and that feels about right. As Oxford and Cambridge are to universities (in terms of age and prestige), so is Winchester to secondary school. Being of a similar age (founded in 1382) and architecture, and with similarly quirky traditions, it really does feel like a mini-Oxbridge.
In the name of full disclosure, I should say that I didn't pay for a tour - my son was apply to the school so I got a tour for free, but I found it pretty engaging nonetheless.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.