I work on the principle that the more expensive the tyre, the more mileage they do so the cost per mile works out about the same as a cheaper tyre which needs replacing more often. This is just my personal observation.
So if you do a higher mileage, use a more expensive tyre. If you do a lower mileage, use a lower priced tyre. Thus after, say five years, each type would would be fully worn and need replacing anyway because of age.
Summer, winter or all seasons depends on where you live and travel. In the South summer tyres all year should be fine. In areas prone to heavy weather, then winter tyres are obviously better.
Sounds to me like what you've got now might be the ideal option for you.