Personal opinion here but I'd never go for a hyphenated domain name myself. There are FAR too many crap/spam/parked domains like it.
If you see the following two domain names, which are you more likely to click on?
www.unbeatablecarinsurance.comwww.unbeatable-car-insurance.comMy own knowledge would suggest that people instinctively know that they're less likely to go off to a link farm if they go for option #1.
As for your questiuon about "i" or "e" in from of the name, if you're going for a hyphenated domain name it will affect you because the SE's will pick up on three words:-
idog
food
tips
That means you'll be low on "food" - 624,000,000 results
low on "tips" - 581,000,000 results
high on "idog" - 599,000 results (which inciidentally is a robot dog who loves music)
AND who will be searching for "idog" when they want food for their canine friend?