Presque Isle can be great for smallmouth, but there's a smaller window of opportunity in the bay. They will come in to spawn and some do stay all year, but very few. After the spawn and early post spawn, you've got to get on the main lake. I've had 100 fish days in PIB with a 3+ average and over 5# on a few. It's rare as I can only get on Erie so often each year and if main lake is an option, I'd rather fish the big water.
There is far better fishing main lake year round. Lots of largemouth in the bay too, not that that's a bad thing. I've heard of some nice sizes but I've never hit 5 pounds personally on LMB at Erie. Seen plenty pics of them though. Just a backup option if you can get on the main lake. And it's still worth it in the summer in my opinion. Caught a few near trophy pike and plenty of 30+ days on largemouth in the early summer before it's too choked up with weeds.
My current favorites are D-shot, Jerkbait, Spinnerbait, Tube. I'm far from the vet on Erie other guys on this board are and I've still got a ton to learn. But I'm proof that anyone can get on this lake and hit triple digits with a buddy, as well as catch (and release) a few trophies.
Last note, gotta respect this lake, as I'm sure you've heard. Your best day on the water can turn into a nightmare with the weather and wave conditions. Main lake is serious and you must know forecasts. I check my apps on iPhone every hour and keep an eye on the sky as they say. Interestingly, I've had days on the main lake fishing 1-2 footers with no issue, only to return to the bay and find 4 footers. Not fun in the little 14' aluminums we sometimes rent. Anything over 3' on the main lake and we usually head in. I've read plenty of horror stories about those fancy $40K flat bottom bass rigs ending up as structure on the bottom of Erie. If I can find a solid 17-18' deep vee by April, I'll be out there much more often and I'll post some reports.