If you take an Escher Juve, to match a Escher Ganger in stats you need:
+1 BS (+20creds)
+1 Will (+5)
+1 Int (+5)
+1 Cool (+10)
+1 Ld (+10)
So that's +50 creds so your premium over an actual Ganger is +20 creds.
For Orlock it is:
+1 BS (+20)
+1 WS (+20)
+1 Will/Int/Cool/Ld (+30)
Which is +70 creds which is a crazy +60 over a basic Ganger though you do get a +1Mv and +1Init which is worth +20 creds I guess and you could maybe forgo one of the WS/BS increases to take you to just a +20 creds premium over a basic Ganger (With Mv and Init advances) if you're not designing an all-rounder plus that's your 5 advances.
For Goliath it is:
+1 BS (+20)
+ 1 Ld (+10)
+2 Cool (+20)
+1 Int (+5)
Which is +55 creds, and +25 creds over a basic Ganger.
So for the 3 "up-to-date" Gangs, the premium for a Juve is only +20 or +25 creds, which also gets you a Specialist (Which doesn't cost anything in rating but is rare to roll up) but the Orlock Juve has some baked-in stat increases that makes them expensive. You're also probably stuck, assuming you play with Sticky Fingers, with some sub-optimal Juve-weapon loadouts that while you don't have to take into combat anymore, do probably bloat your super-Juve a bit.
The main problem I have with promotion/advancement is the glacial pace of XP gain which means I've rarely seen a Juve accrue enough XP to promote. I don't think, outside of Orlock Juves, they are overly bloaty for the 3 refreshed gangs. Cawdor, Van Saar, and Delaque Juves are pretty bloaty however.
EDIT: Specifically on the Orlock Juve, I think they are too expensive. 35creds compared to the 20/25 creds the two other refreshed Gangs get seems a little too expensive for generally similar stats. I'm tempted to give them a small nudge down in cost to 30creds
Your numbers are right but why would you ever take the stats that are just bloating out the cost in the current ruleset?
Juves in the House of X books seem to be started towards being close combat fighters and no longer promote to champions so for Escher and Goliath you can just take a BS advance and you have a fighter that is just as good in the core stats and is cheaper.
Or even better you can lean into their better stats and take extra movement (and extra WS, S, or T) and have a better close combat fighter.
The trick with juves is that you are not trying to make a better balanced fighter, you are trying to make a better specialised fighter for a similar cost.
I do 100% agree that experience gain in the current ruleset is too slow for everyone and I wish that the d6 Xp just for taking part in the battle was still a thing.
Edit: as this is the house of Iron thread I should add that I can’t see Orlock juves actually being useful. Without a starting bonus to either WS or BS it makes them hard to build into something worthwhile for a good price.