I concur!
We had some honorary type fellows that in 6 years the extent of their involvement was them coming to fancy dinners (but not sitting with students

) or lecturing at big subject events only.
I found the (bookable in advance!) subject specific session of my college open day very helpful to finalize my choice - because you actually meet the tutors likely to be directly involved in your education & perhaps some current students.
These things do change - so I could speak about how utterly awesome my college was for medicine 2003-2009 (e.g. quality, number and range of tutorials both preclinical & crucially clinical, collections/mock OSCEs, perks as below, the medic society/dinners)... but already there have been changes in key people involved - so the experience would be different now. Libraries will vary but the University ones really are very good too. Also variable are grants (books are standard but some also have equipment and elective grants) & other medic perks available (like rent rebates when on clinical placements/elective) - but these are the sorts of things that finding out in advance about will be a mission...
Now the number of places available is something that you can find out about in advance & was one of my college shortlisting criteria - I wanted a 'medium' number of medics & 6 seemed about right!
The other subject specific parts of college choice for me I think were location (for both the Science area and hospitals which are towards the East), clinical places, graduate accommodation provision (thinking long term here!) & slight seduction by a fun sounding society (Port & Cookies!

) & some Big Names.
But - the other things to bear in mind is that the overall department work hard to minimize the impact that College choice might have on your overall chances of getting in by formalizing 'pooling' - so that more successful applicants will have offers from a College other than the one they applied to. Overall probably a good thing - but means may be best not to get your heart set on somewhere...