A few questions.. what does invisalign feel like when it is in your mouth, and is it better to get invisalign rather than regular braces? If so why?

Fairly easy to figure out why someone would want Visalign braces rather the unatractive metal braces. Visalign are more comfortable to wear, can be installed by easily popping then in your mouth and are less noticeable.

Only downside I can think of is the expense of having new ones every two weeks.

Sorry, meant INVISALIGN.

I also understand there are more limits to what it can do, on some serious issues the normal braces will be required.

So often it is done after discussion with your dentist and from what can or can not be afforded

Fairly easy to figure out why someone would want Visalign braces rather the unatractive metal braces. Visalign are more comfortable to wear, can be installed by easily popping then in your mouth and are less noticeable.

Only downside I can think of is the expense of having new ones every two weeks.

Does it feel like flossing and does it go between your teeth?

Doesn't go in between teeth, that is the beauty of this system. If you need this done, go back to your orthodontist and have him give a demonstration, so you know exactly what is involved. A professional opinion is always your best bet and won't cost you anything if you are considering this. However, don't know how old you are, and you must realize in mature individuals, teeth are already set in bone, but only somewhat malleable. It is your investment so you need the best advice you can get and that is only from a professional opinion.