I have a BDP-2 with upgraded IAD board. Also have a few BS Node 2is. Connected to my Schiit Yggdrasil A2 and Denafrips Terminator, the difference is definitely noticeable, particularly comparing AES connection from the Bryston compared to SPDIF from the Node 2i.
I'm not sure how much better the BDP-2 with IAD upgrade is compared to the BDP-1. You could ask on the AudioCircle Bryston forum. If your DAC doesn't have AES support, the difference is probably not quite as significant.
As fuzztone pointed out, the Bryston does not have the same functionality as the Node 2i. In my opinion, the Bluesound UI is a big step up from the Bryston Manic Moose software, but it all depends on what you are looking for. I used my Bryston just for Roon and for that it works great. But if you want to use Spotify or internet radio stations, the Node2i is the better choice.
I am planning to sell my BDP-2 (if you are interested, send me a PM). I just got a Denafrips Gaia and I am connecting my Roon ROCK server directly to the Gaia which is now connected to my Terminator DAC through i2s, so I don't need a streamer in this system any longer. I still have a bunch of Node 2i's connected to systems elsewhere in the house so that I can play to multiple zones through Roon, but I'm using the built in DAC on the Node2i for these systems.