But if Cinestill ends up being the only place available to get the new 250D with anti-halation (assuming I'll be able to get it at all)... then I'd buy from them. They probably market it as 400D, but knowing what it is, nothing stopping me from just shooting it at 250 and developing myself in ECN-2 minus the remjet bath.
If Cinestill will indeed have access to Vision3 films with AHU the 250D will be film that I'd be least interested in. Portra 400 is better or at least as good, doesn't need ECN-2* developer and is not more expensive than Cinestill 400D. On the other hand there is nothing like 500T or 50D available among the regular C-41 films.
* You could argue that you can mix your own ECN-2 developer at home and save half a EUR that way, but I'd guess there are very few people that will spend 20 EUR for a roll of film and would then be priced out by (relatively) cheap C-41 processing.