you know what can make hps so much cheaper than LED`s ?
If you need a new bulb, order one, put your old one in the new lamps box and kick it, complain to the shop it arrived broken and ask them to send a new bulb again
free refills on bulbs, is a perk you can`t get with leds, then again leds can`t be sharp glass that cuts your hand, so there is that
I`d say these cobs running @ 40 to 60w that are cool and efficient in reality are probably not much better than a 1000w hps lamp running @600+super in a cool tube
but they do use less glass and are much easier to aim and build yourself, not that I`ve even built a hid driver but that`s kinda the point with hps the driver is about all you can DIY so you can`t really do too much custom work on them, I mean with hps you`re also pretty much limited to 2800k very efficient for how old they are but you get a load of orange and warm light no choice in the matter
but with cobs people now get an easy to use, cool light that can match or even beat hps for GPW yet they are not limited in size or light colour and you can build the array, driver and such yourself
they are pretty well suited for the DIY grow light crowd
and with 1000w+ cob and smd chips around now it won`t be soon till it`s considered easier to use leds, maybe 5 years or so
I mean 1000w+ smd`s make some mean side lights or even top lights and leds are easy to aim and less of a fire risk, cooler too so sometimes it`d even be worth getting less GPW because you can use more power in the same space and get more yield that way
sometimes what you can get out of the space matters more than what GPW you could get if you could get a certain light set up to work in that area
LED`s give off less heat I like them as I can normally run 2000w of led in a room where 1000w of hps would be too hot happens a lot, or I see people using 1 x 600w hps and 1 x 300w led as it`s too hot to use a 1000w hps but they wanted more yield......
but loads of 50 to 100w cobs are great as like T5`s and other tube lights you get less shadowing and more even coverage
personally I like 300w+ or 1000w+ cobs as I don`t like to have too many lights to look after