Sounds like you are really thinking hard about the best choice, Rough

Keep thinking about what you want to do with riding

Mountain bikes and 'comfort' hybrids are quite a lot heavier than road bikes... hence the "squirrely" feeling when you tried one. But if you want to ride on sealed roads, at speed, and get up hills at a good speed, then a road bike is what you want.

I have a mountain bike and a road-racing bike... I find it really difficult to adjust to my heavier, more unweildy Black Thunder.

Where you will ride, and how you wnat to ride will help you make this decision.