HD3 accel to HDX1, Happy?

[DetroitT]

Hi.
Close to this big move. Most of the positive post reference HDX2 systems rather that just one card. My interest is HDX-1

I'm borderline going HDX1 (HD I/O 8-8-8) but have a few reservations.
AAX is getting there so not the direction of this post.
Rather for pop-music productions where 120-160+ voices @ 44.1KHz is most common.
I also convert stems to surround for music videos and short independent films.
(Currently 5.1 discreet-PCM) HD3 maxes out quickly here.

My system (my investment)also prefaces 5 other rooms (HD3, Magma solutions)

HDX1 (One card only), on-par, betters a bit, betters allot an HD3 or stay and add more accel cards

Your opinions welcome.
Thanks.
T