At the risk of sounding like a Hilton apologist, I don't see a program with measurably more rewards out there.

My most recent HHonors redemption was at the Hilton Paris ADT and before that the Hilton Barbados, both excellent hotels as discussed here on FT. Let's take Paris, after these changes a five-night stay will be 200,000 HHonors points. Let's compare that to similar properties from the other major chains.

HHonors = 200,000 points
Marriott = 160,000 points
SPG = 80,000 points
Hyatt = 90,000 points
IC = 200,000 points

(Note I picked five nights because that is most beneficial to Marriott and SPG with their 4 nights - 5th free on awards).

Now, how about earning, let's assume top tier with each and you are using their top co-branded credit card, the points/dollar come out to:

HHonors = 10 base + 5 Diamond bonus + 9 Surpass = 24 points/dollar
Marriott = 10 base + 5 Plat + 5 Premier card = 20 points/dollar
SPG = 2 base + 1 Plat + 2 SPG = 5 points/dollar
Hyatt = 5 base + 1.5 Diamond bonus = 6.5 points/dollar
IC = 10 base + 5 Plat (RA?) bonus + 3 credit card = 18 points/dollar

So, how much spend for each:

HHonors = $8,333
Marriott = $8,000
SPG = $16,000
Hyatt = $13,846
IC = $11,111

Of course, there are wrinkles to each program that makes this not exactly what we want. HHonors we can double dip, it may be more appropriate to do this on a points + points comparison, which would lower the cost to $6,897. SPG, Marriott, and Hyatt you would get their "welcome" amenity which you can opt for more poitns, 200-1,000 points/stay, so that would effectively lower their cost a bit. They all have promos from time to time, I'm sure some would say IC's are the most generous.

Quite frankly, Hyatt is my favorite of the bunch anyway because of their annual Nights after Nights (now Next Big Thing), but Hyatt and SPG have a huge problem in that they don't have as many properties combined as any of the other three.

I think Hilton's lounge access policy for Diamonds is a big plus, others will say SPG's suuite upgrade for Plats is where it's at. IC has good benefits for Royal Ambassadors, but my limited understanding is that's a tricky status to get (based only on stays at IC brand hotels, not the cheaper hotels).

As I mentioned prevoiusly I gave an advantage to Marriott and SPG by using a five-night stay, you get the most benefit from them in exactly five-night increments, Hilton VIP awards you can do 4-14 days and still receive some benefit.

Note that if your goal is earning hotel stays through credit card spend, the Surpass card blows away the competition, especially since you can earn top tier elite on spend alone.

In the end, while I'm not arguing this is not a devaluation, I always thought HHonors was ahead of everyone before, which is why I favored them, and it seems like now they're roughly even, not behind. Now that Hilton has done a big devaluation I would guess it will be someone else who devalues their program next, but that is just a guess.

Edited to fix math errors pointed out by VA1379