is a subject much discussed in electronics books and advice and I'm going down the fuse route, instead of CBs (mostly).
Questions that need to be considered are:
What items are there that are so critical to flight that you need to have access to them while up in the air? I have two ('backup battery' circuit for Rotax 912iS and battery isolation for a Lithium battery....madatory for the UK and, I think, a good idea). For these two circuits I'll have 30A CBs in the panel. For everything else, so what if I lose the radio, transponder, EFIS or iPad charger. Look out the window and do what we did before we got all that kit.
To me the more important thing is WHY has that CB popped? They don't do it just for fun and that means there's a snag with that system. Is being up in the air really the time to start trying to second-guess why your iPad charger has shorted? Do you need it so desperately that it needs to be re-set now or can you wait until you're on the ground?
Space, weight and cost are also considerations but I think the two points above are more important.
Because of all this I'm going down the fuses route. I'll have the fuse boxes (I'm using one as the main bus and a second as the avionics bus) under the panel where I can gain access to them but, realistically, only on the ground.
I like the Vertical Power system and I think electronic circuit breakers are a great system (MGL do a reasonably priced one) and if I were building an RV or similar then I'd definitely be looking at one. However, for my aircraft (a Eurofox) the flaps are manual, the trim is manual, wig-wags are pointless because the landing lights are tiny and in the nose and the starting system goes straight from the battery to the engine. Yes, I can use the ECB as a great way of programming and controlling the CBs but a lot of the functionality of the VPX would be wasted and that's why I opted not to go down that route. If I had all the gizmos above then I would be sorely tempted
So, to answer the question, the panels you see either have an ECB or they have fuses hidden behind the panel (or similar).