Haha tough call. That is the nature of this illness hobby.. Even when we are the most satisfied or seem to be content, if we see something that is a bargain and we have the wonga then its gonna happen. I've actually been quite happy when I've bought an amp and it hasn't been as good as my favorites. This gives me more peace of mind that what I do own is the best I'm going to get. Problem is, when you get something that is clearly superior to what you already have... Or in your case has a sound that you fall in love with. This happened to me with my new QED and its fantastic hp stage. Luckily it only worked out for one of my headphones. Otherwise I would have sold everything and went on a mission to buy all QED amps out there haha.
Having said all that, its nice to have some variety. Live with a sound for a few weeks then have a change around. I'm still at the stage where all my amps are budget to mid price and so I don't just own 2 or 3 of the best (I've got 12 amps at the last count..) and so I play around with set ups etc. It's fun!
You've got some of the best of the best Moody, if you give up one of them, you'll only look to seek it out again. Coz you'll miss it!