Although I casted my vote, it is not an easy question.
There are pros and cons to consider.
A grand cathedral with a large choir and big pipe organ (100 ranks +) being played well, the architecture, ambiance, etc. would be just lovely. Such a church would most likely have the funds to have a large and dynamic music program.
On the other hand, as a congregation member, you can easily get lost as just another number in the pews. Or if you are just visiting you may like the option of not sticking out as the new person and being able to slip away after service. There's also a chance for more politics simply by virtue of the fact that there will be more issues, concerns, and more people.
A small church would theoretically have less politics due to less people, you might feel more welcome because people will notice you and you won't feel lost as just another number. Worship would feel more intimate. On the other hand, if you are just visiting, you may not like being noticed as the new person very much. You will probably be needed more in the church community and there is probably a greater opportunity to volunteer somewhere, especially if it is an inner city small church.
While a small church may have a smaller choir and organ, there is something to be said for quality over quantity. You can still accomplish great things with a small but committed choir. The fact that one can only find high quality music in cathedrals and that small churches do not have much to offer is a false stereotype. On the other hand, cathedrals tend to attract qualified singers or those aspiring to be such as well as paid subs. It's also more inspiring to play Carillon de Westminster on a 100 + rank organ than a significantly smaller one.
These are all just theoretical musings from past experience on my part. I could go on but I'll stop here. In the end I picked the cathedral. I know that I can serve more people, do greater things, and give God glory on a much larger scale in such a setting. Since I will live only once and in the final anaysis I want to tell God that I made a gift of myself to others as much as possible, I'd prefer to make the biggest difference I can. Cathedrals also tend to be in downtown cities which means there's a greater need for outreach, and a greater responsibility to use the greater resources to help others less fortunate. So yet another reason to pick the cathedral.
Whew! (Yes, I know, I have been told before that I think too much and over analyse!!!)
I'll stop now.