This has been a rather interesting thread to sit back and read! So far, only one person has come close - Paul Dye!
Basically, all of you who think we do it because "it's cool", or "it costs more" or "it's the way it's always been done", or any of the other proffered opinions are just dead wrong.
#1, we do what the customer wants. If the customer wants breakers, we use breakers. If the customer wants fuses, we use fuses. Either way, the customer has to run the exact same number of wires up to the panel, so that's a moot point as well.
Overally, if we are to assist a customer in choosing, we typically will look at the equipment first. If it's a VFR only plane with little to no avionics in it, them perhaps fuses are a great way to go. However, if you have a high end panel with high end glass in it, then CB's are the way to go. Why, you ask? Wll, Paul Dye pointed out a few reasons. Usually the high end EFISes are made up of a number of components (Screens, AHRS, MSU, etc..) that are all powered and need to be protected separately. Along these lines, when you have multiple screens with multiple boxes behind them, you'll need a way to be able to power up certain components separately from other components - when doing software loads, upgrades, calibrations, etc.. All the way from GRT, AFS, Chelton, Garmin, etc.. it's very usefull to be able to power up the components individually on the ground.
Personally, I think sometimes a mix of both is a good solution. Unimportant things could easily go on fuses, but important things should be on CB's. Believe me, we don't have a personal need to try and convince a customer either way, but some of the equipment does. Some things you should be able to reset. Those of you heavy iron drivers out there know that certain ground checks get done with certain breakers pulled and then reset (especially on the sparky's). Same goes with the higher end EFISes and their relative software loads, etc..Another thing is the ability to quickly and selectively shed load.
Anyway, I could ramble on about this, but I think that everyone gets the idea. We do what the customer wants within the reasonable limitations of his choice in equipment then use the equipment choice as a factor.
FYI, Fuse blocks for us are actually easier for a panel shop to do than CB's. No separate buss bars to attach, less wiring, etc.. and YES, we do an awfull lot of panels with fuses in them. Even on panels you see with lots of CB's, there are often time multiple fuse blocks behind the panel (going on the sub-panel or wherever).
In the end there are lots of reasons, but most of them are not what people have been guessing. It's usually well reasoned and logicall, along with customer desires.
Just my 2 cents as usual!
Cheers,
Stein