Yes, but potentially a lot more comfortable. Personally, I find the long run on the Piccadilly Line very uncomfortable, particularly when it's busy (you can end up standing). Even when seated, if you're tall and broad-shouldered, it can be agony on the back after 15 minutes.

I come into London at King's Cross, and will generally use the HEX rather than the direct Piccadilly Line service. There's no time advantage, and it's expensive (although I'm not usually paying) but it feels like a much more pleasant journey.