I'm in Ohio so our Direct Marketers system may vary some from yours, but the key things in contracts here I look for are:
early termination fees, contract renewal terms. The ETF's are usually straight forward. Contract renewal can be a bit trickier. Be aware of the notice of renewal and your responsibility. We have one company that states that you have 5 days from the date of the renewal notice to respond IN WRITING or you are committed. That is total BS. Also BEWARE of variable rates. Had a friend in PA who let the contract roll from fixed to variable and they were severely gouged. The variable rate computation is usually one where you have no idea what it is based on as it is a function of whatever they deem the rate to be.
You are looking at 36 months so it's not an issue but I'd advise anyone to avoid very attractive come on rates for just a few months that reverts to a variable rate. The companies here are banking on a large number of people overlooking the renewal, just as my friend in PA did.
As to your offer, the rate you indicate you received is about half a penny a KWH better. If you use 1000kwh a month then that saves you $5 a month. So you're ahead every month until the Penelec rate is (if ever over the course of the 36 months) under yours. You have the $100 as bank plus your savings. If the reverse is true, that is their rate is a half a penny under yours, then you have 20 months covered, or more depending on how much you saved before that happened.
BTW I just signed a 41 month fixed rate in OHIO for 5.3¢ vs the current utility rate of 5.9¢, but no gift card.
Edit: P.S. in Ohio if you move and stay within the supply market the contract moves with you. If you move outside of the supply market then the contract is terminated without a fee to you.