Moyn, here are my experiences...
Are you getting a whole new kitchen or just replacing appliances? Either way, congratulations, new kitchen stuff is always fun. I've been cooking on your new combo for 5 years now, here's what I've experienced:
Cooktop: It's really durable. Don't worry about scratching it. Mine still looks like it did on the first day. That said, I unhappily follow the guidelines about not using cast iron pans . Follow the instructions and you'll be using it for years. The important thing is keeping it clean, and your instruction manual will tell you how to do that. A good non-abrasive liquid cleanser will clean it up to sparkling new in a jiffy. The knobs go in the dishwasher. You'll love having the extra space on your countertop when you're not using it. One tip, if something is getting too hot or about to boil over, just slide it over. I've seen people try to turn down the heat and do all kinds of weird things when cooking on mine when something like this happens. Just slide the pot over and it stops. Simple enough.
Convection oven.
I love the convection oven for roasts, meatloves, baked chicken, casseroles, pizzas (I line my oven racks with unglazed terra cotta floor tiles, and dump the pizza directly on it from my peel, the results are very close to a commerical pizzaria), etc.
I have given up convection baking for cakes, pies, and especially, cookies! I have worked and worked within the guidelines and my results are always the same: too brown crust and not finished baking. The cookies have performed especially bad with convection. I've tested from the same batch of dough (convection vs. regular) and the results were jaw-dropping. With convection, my cookies spread out into greasy thin overly brown and not completely baked. Using the same dough, these cookies were absolute perfection in the regular oven. I've finally just gave up using convection for these items.
Good luck and have fun!