Since this is your first post i wll go easy on you.
1. If you want to make posts like this then post in the newbie forum
2. Always search first. Really the search function works quite well on this forum
Now to answer your question. it will look fine on a 7" touchscreen. Many people including myself use copilot. IMO it has one of the best interfaces besided MapMonkey (although if you live in the USA you have switch maps so no long trips)
Personally i use for the most part iGuidance 2. It's interface needs some work but it's functionality is awesome