Been going here for years, so maybe you could consider me a regular.
The staff are great, and really that is what sets this Firkin apart from all the millions of other ones.
The Churchmouse is very active with the community, and all sorts of events take place there through the year. Word of warning: if there is a church street event happening, the ChurchMouse will be jammed.
Like all Firkins, the menu is a bit lacking for those with eating restrictions (vegan, vegetarian) but its a pub so that shouldn't be a surprise. Lots of specials, all the time, and their cookstaff are fantastic.
And they have guinness; what more could I ask?