Are the Great Lakes a good alternative to the sea, as far as visiting or living there go?

I don't know if I would say they are an alternative to the sea. They do have water and beaches, but winters in the Great Lakes region can be brutal. It is important to note that the Great Lakes region has been called the "Rust Belt" for a reason. I happen to live in the Southwest, but I do think the Great Lakes region will be reborn someday and turn out to be a pretty nice place although it has a ways to go. Your description seems to indicate you live near a seacoast already. Have you considered inland? There are many other places in the country's interior with smaller bodies of water which are nice places to live. You have to be willing to do some research and parse out what is really important to you, but you do have other options.  

Sure is lake Michigan is the best of them .

I guess I'm not sure what point that anonymous (the long post) is trying to make. I can buy a comparable house in Gulfport MS cheaper than in Erie. And the culture in Gulfport is going to be a whole lot different than in Cap Cod which is different than in LA. 

I guess what I am trying to say if that there is no way to say that coastal towns are all___________.

And all to say the great lakes region is a terrible place to live is when there is over 4500 miles of great lakes coast line in the US. You can't possibly have lived in all of those areas long enough to make a judgement.

Watch the Weather Channel sometime within the next couple of months.  They willl invariably feature stories about massive lake-effect snow on Buffalo. It's quite common for them to have three or more feet of snow dumped on them in a night.

Granted, we don't have sharks in the Great Lakes, but we do get gales. Those are close enough to hurricanes to make me nervous. They're capable of sinking ships. 

At least we're not constantly on fire like California.

The Great Lakes region is not comparable to the coast by any means. You might as well be asking whether living in the mountains of West Virginia is comparable to living in Aspen, Colorado. 

Most of the Great Lakes region is a very depressed area, economically. The specific cities that you've listed are all terribly depressed. Western NY is a far cry from Long Island. Erie is not a great area. The Buffalo and Niagara Falls area is statistically one of the worst areas in NY state. 

The climate is completely different. Coastal areas get much more mild winters and their winters are far shorter. Buffalo and Erie frequently see blizzards whereas places like the Jersey Shore or North Carolina get much less. Then of course there's the job situation and the cost of living. In Buffalo or Erie you can get a 2,500 square foot home for $175,000 whereas in Highlands, NJ or Nags Head, NC a 2,500 square foot home would be considerably more expensive. 

There's also the cultural factor. You want to do karaoke at the bowling alley? Then move to the Great Lakes. 

The Great Lakes region is a terrible place to live. 

Are you asking a question or advertising for the Great Lakes? 

I'd say so, if you like to be near water, but don't think they can't be dangerous because they are lakes.

Why not go for one of the  towns along Lake Huron or Lake Michigan?