You cant get 250K for a guild anymore cause they level faster now, maybe 80K if you are lucky.

I made my guild for the travel perk which they removed but I am very happy to run a large guild, although we have over 350 level 90 members we never raid since the old core left .... bleh but still its nice to be guild master of such a large guild. All the monies I put back into repairs, I dont put cash into the guild, but I dont take any out either. And I just tell them the bank in closed and thats it so I can move stuff around between my toons simpler.

Bottom line if you are ok in your current guild I would stay UNLESS you want to build your new guild up to 1000 members, otherwise you gain very little.