Restart..
Well, Never mind with Ruby and Sapphire, you can do everything and more (does that even make sense?) with Emerald, so really it's 50:50 between Kanto and Hoenn.
The starters are better in FRLG, put frankly. They're bulkier, in appearance and in battle. The likes of Sceptile and Blaziken are taken down too easily. But that's only minor, really, as you don't even have to use the starters.
Nostalgia.. It's when we feel really good about something that happened once, and to experience it again is to be nostalgic. You can probably imagine how nostalgic it feels for veterans of Gold and Silver to be announced.
Anyways.. I'd play Emerald. No particular reason, but once you get into the swing of it you'll be addicted. FRLG.. It's good, but the initial storyline..
I don't know. Sorry. Try closing your eyes, and just do eenie meenie mynie moe.
Seriously.