There's no "good one", since the different series represent design tradeoffs other than just price. Some people want the lightest device, some the most powerful

There's no "good one", since the different series represent design tradeoffs other than just price. Some people want the lightest device, some the most powerful, others want the longest battery life. You can't have it all. If you just took the most expensive ThinkPad, you'd probably end up with a P-series workstation, which is far from most people's definition of "best". And that's okay.