Suspending it will keep it in the "inactive memory" area, meaning it should boot faster when you restart it, it will have it stored in cache too or something like that. Booting it after you shut it down completely it will need to go through the harddrive, locate it and run all required files again for it to work. If you need to do something that requires a lot of memory, but not on windows, I'd suggest just shutting it down if you aren't going to use it again soon. Otherwise, suspend shouldn't really affect performance much for basic functions such as web browsing.
I think I'm correct on this... If I'm not someone will be sure to correct me!