IMO (from an investment standpoint), no. Ultimate packs are a bit of a cash trap in my opinion.
Consider this: you get 7 cards for 40 credits, with 1 rare guaranteed. 7 cards for 70 credits with 3 rare guaranteed means you're paying 30 credits to guarantee 2 more rares. First of all, that's 75% more credits.
With an Elite pack, you're paying an average of 5.7 credits/card. With an ultimate pack, that average cost is 10 credits/card, which is 75% more expensive (!!!!). This means that your Ultimate pack needs to give more than 75% more value than a regular pack to be worth it.
Next: We can consider an elite pack to be 1 rare + 6 randoms, while an ultimate pack is 3 rares + 4 randoms. The only difference is 2 rare cards instead of 2 randoms, and you're paying 75% more for that.
BUT WAIT, maybe that's worth it?
Going to take small sample from 6 NB/Elite packs I bought last week.
In these packs, I got an average of:
1 rare, 2.6667 uncommon, 3.333 common.
This tells me that:
1. you will most likely NOT get unguaranteed rares.
2. you will average approximately 1:1 uncommon to common card.
Second of all, rare cards are not necessarily the most expensive types of cards in a deck. I'm going to look at a few clans so you can get an idea of a typical pack (these are the 4 clans I picked out for my elite packs). It's worth mentioning that PCats have extremely high value uncommons, so you should pick them for your elite packs.
PCats (Crs omitted).
11 rare cards, with an average value of ~3780 (crude math by rounding to the nearest 100s)
15 uncommon cards, with an average value of ~5700 (granted, most of this total is in Charlie and Yayoi).
14 common cards, with an average value of 390
11 rares, avg ~9260
10 uncommons, average 1740
10 commons, average: 250
11 R: 8300 avg
13 U: 2500 avg
16 C: 400 avg.
39 R: 7000 average
42 U: 3400 average
44 C: 400 average
This would mean the expectation values for the two packs you'd buy are approximately:
ELITE (40C): 1R, 2.7 U, 3.3 C = 17500 / pack
ULTIMATE (70C): 3R, 1.8U, 2.2 C = 28000 / pack
TL;DR: you're getting 60% more value and paying 75% more. so no.
1. Given a rarity, you have an equal probability of getting any card at that rarity (probably true or close to it, from qualitative experience, it's not harder to draw Lizbeth [Jackpot] vs. Amiral Coco [eh] for your rare)
2. Small sample size. You can probably get more accurate with more packs, but this should be relatively close to the real deal.
Feel free to comment, I'd like to have a discussion of this.
While the end result probably won't change, I think you can increase the EV of the Ultimate pack by NOT picking Pussycats for it. As you pointed out, most of their value is at uncommon, with quite a low value at rare. So they make a good choice for Elite pack, where you get almost 3 uncos for every rare, but a terrible one for Ultimate where you'll probably get more rares then uncommon.
From a quick glance Frozn should be a good substitute, with an average rare price around 9k.
If you match Clans correctly then the Ultimate pack is worth it. When I buy Ultimates, I ALWAYS choose Vortex Huracan Frozn right off the bat, because if you look at their rares, you have a VERY high chance of pulling something worth your money (Kaliandra, Kinichaw, Dregn, Shaakarti, Naeole Rad, Thorpah, Stompah etc) while adding the least amount of max rares to the pool. My last clan is usually Piranas (another high value to ratio clan) or a clan that I would really like to pull a few rares from, because of some preference or another at the time.
If you pick clans like Nightmare that have a huge number of rares, but only two rares of any real value (Kolos & Karrion) or GHIST now that they have Mechakolos, then you will most likely come to regret it.
I actually mapped out all the best & worst clans in detail in my guild message board, but heres the short version: Don't choose Bangers Jungo Pussycats or Freaks unless you REALLY want a card from there and it's not in NB. NEVER choose Montana or Roots, they have abysmal average values in their rares and will ruin any profit you couldve stood to gain.
BUT at the time I charted their values, they also had some of the smallest amounts of rares (7&6 respectivly)
Buying Ultimates for me has gone either way, but I tend to get Lucky. I pulled a Kolos, Cortez and Dregn (both being when they were valued twice what they are now) in one pack, probably the best I've ever gotten. Although that being said I've opened some really crappy packs even when choosing some good clans. It all comes down to the clans you choose, but I'd much rather do the Titanium than any number of NB or Elite which I have never had any luck from.