The COBS themselves are only a part of the cost, the efficiency boost from going to the CXB3590 is way worth it. Going off the chart on COB efficiency the Vero 29 shows 42% efficiency at 1.05 and 37 watts. The CXB3590 CD bin runs 56% efficient at 1.4 at 49 watts. I could be wrong but I believe this makes the CXB3590 cheaper per watt then the Vero29, because if you didn't care about efficiency you could drive that CXB3590 a lot harder and it would produce 43% efficiency with putting out 104 watts! That is twice as hard as most people run them and still beats the Vero29 efficiency. Plus it would take about 3 Vero29s to equal a CXB3590 watt per watt at the same efficiency level.
My opinion for a budget build with the future in mind, look at the CXB3590 CD and run them at 1.4 for 49 watts each and 56% efficiency. And run 12 of them for every 1k light you replace for a total of around 600 watts. Should give you fairly similar yield - but I am no expert just going off stuff I have read in the past and that is what I plan on doing. Also the more efficient a light is, the less heat it puts off. So going off what I have read, those CXB3590s should put off a LOT less heat then the Vero29s running at the higher efficiency levels. I seen a chart somewhere the other day about heat output and it's amazing how fast the heat starts to go away once the efficiency levels go up.
So bonuses of going 3590 right now - A lot lot more efficient, won't have to upgrade in a couple years becuase it is so outdated, a lot less heat then the lower efficiency COBs, less of them to wire up since they are 50 watts each. Should be a decent boost in yield comparing watt per watt between the Veros and CXBs based on efficiency levels. And really the price isn't that much different that I can see. I haven't looked into the Veros so don't know what they go for but the Cxbs aren't too bad considering how fast they pay themselves off and might even be cheaper then the Veros watt per watt comparison. I am sure someone knows if the proper person would read this.
Edited to add - Not sure what the 1000HPS runs at. But I think it is hard to compare appples to apples because it doesn't have as much usable light for the plants to use as a COB does. Since only certain spectrums are used by the plants. I remember Supra laying it out onetime when I was looking into them a year or so back but I really doubt I could ever find that post again. This type of stuff should be stickied at the top. For a beginner into LEDs it is almost impossible to learn what you need easily you have to go through tons of pages of different posts and try to piece it all together. All the info should be listed in one sticky at the top of the forum section. With links on every question someone asks. I still don't know a lot of things I'd like to know because it is hard to find the answers looking through hundreds of pages of posts.