@John Zhang I live in Clermont and know Bella Collina well and do a fair amount of business in Lake Nona as well. Bella Collina is incredible and hard to compare to other communities around Orlando. It started many years ago and failed during the recession. It was brought back several years ago and now has a mix of luxury homes, mixed with more traditional builders like Dream Finders and Toll Brothers..both building great homes and golf course lots are available.
Montverde Academy is a big draw for this area and many more communities will soon surround Bella Collina with the likes of DR Horton, Pulte, Taylor Morrison and others building more spec type homes. The commute from there to downtown Orlando (<30), Disney (<30), Airport (30-40), Tampa/Clearwater (1.5) Cocoa Beach (>1). So it really is convenient and still growing. Taxes will be lower in Lake County too.
Lake Nona is growing at break neck speeds and is looked at as more affluent overall due to the high paying jobs in the area. Many space related jobs will live in Nona and commute, not to mention all of the tech and health care, so it will continue to be attractive and appreciate very well. To me, the infrastructure if already lacking and retail business is still playing catch up, so you have to be willing to deal with that. Taxes are higher in Orange County too. IMO, the traffic patterns to Disney and Downtown Orlando are something to consider as they can be more congested even though the distance is similar to the Bella Collina drive. The airport and East coast beaches would be a plus if those are important to you.
We have toll roads everywhere, so that is worth mentioning. They add up pretty quickly and will be needed to get anywhere from either of these locations. Both areas are experiencing quite a bit of growth, but in Bella, you will be East of most of it and it shouldn't affect you as much, Lake Nona is congested and will be for years (depending on where you wind up).
I would also throw in Windermere if you haven't considered it yet. It provides 'status', luxury, location, great schools, prep schools/academies. It is also Orange County, so taxes will be similar to Lake Nona. It is very convenient to Downtown, Disney (you will see fireworks nightly!!) and higher end shopping and the best restaurants around.
Hope this helps, happy to discuss further if needed.
Best of luck to you!