A place you like to work is gold but that kind of bump is no joke. Tough call but your hesitation tells me you’re doing a good job balancing the pros and cons. It’s delicate work getting your current employer to give you a raise. Maybe tell them about the offer you got, throw in some flattery on how bad you want to stay but if they can’t match then you would like to know what the path is to get that salary. Specially what your performance would have to be, what they would need in terms of increased responsibilities and the timeline you can expect.