Just installed ours and only used the MW portion as the rest of the kitchen is not finished. (It did make awesome bacon and perfectly reheated chicken/pork and veggies)
What do you plan to cook in it?
If lots of baked items - probably not a good choice.
Casseroles - probably just fine.

I am not a huge baker. I am wondering about roasting or baking some chicken with potatoes when it is just going to be my children and myself.
Does it really work or is it really an oven?
Thanks.

It's a convection oven with an overhead 'broiler'. So roasting and baking are just like any other convection oven, ie very good. Having the heat element above allows browning and crisping.

The Advantium is a combination speed oven and convection microwave. It has 4 heating elements: standard microwave magnetron, a convection heating element, a radiant heating element on the bottom, and a halogen heat lamp on the top that provides crisping and browning. Although you can program each of these elements yourself individually, the oven comes with preprogrammed settings for common things like baked potatoes or tater tots. In theory, it can do all of the things a microwave and a regular oven can, including grilling and broiling. I have never used mine for broiling. Amongst other things, I think there would be a lot of splatter that would be difficult to clean. I have used it to cook casserole dishes like mac & cheese and lasagne. These have come out fine. They even get browned and crisp like a regular oven. It works very well for baked potatoes and tater tots. I have also roasted vegetables, like brussels sprouts and cauliflower. This came out well, but a regular oven is better. Haven't tried pizza, but it should be OK. I have not tried to roast a chicken. In theory it should not only do this well, but a lot faster because of the m-wave. I haven't tried baking cakes or cookies, but it sounds like you wouldn't be using it for that either. I use it mainly as a microwave, and in that capacity it works fine. I think it works well as a microwave oven that can serve as a 2nd oven, but I'd be hesitant to rely on it as my only "regular" oven.