Root prior to 2.2 or not?

[nailerdog]

Rooted my original D1 and flashed a custom 2.2 ROM and loved it.

I'm now an unrooted DX user. I'm going to load 2.2 shortly but have a couple questions.

If I root on 2.1 will my root be maintained on 2.2?

If not can 2.2 currently be rooted after upload?

What are the primary reasons to root on an X with no custom ROMs and bootloader locked? Remove bloatware and is WI tether operational?

Thanks