Demo both naim streamers if you can. I have the NDX 2 in my all naim system, but I did demo the ND5 XS 2 and it was really good as well.
I have a LUMIN A1 in my non-naim system and it’s fantastic. I’d say the NDX 2 and Lumin A1 are in the same league, but with different presentations. The NDX 2 has the edge though.
Of course the A1 and T2 are quite different, so the comparison may not be too helpful!