First stay away from rollitup, this is a place for kids, second I always get shit replies here for telling the truth. Think of quantum boards, everyone talking miracles about them but almost no journals and most ppl talking about them without having them, same goes with cobs, its cool to say you have those, its the new trend, I had to buy my cobs just because no one would give me real input and wanted to see it for myself... ...but now to the important part:
I own a mars 900w and a timber 6x cob citizcen clu048. The mars kick the cobs ass any day on production and quality, the mars was way cheaper than the timber and got double the yields, way better phenos and better customer support by far. The timber makes the power bill way lower (I dont care about that thou) and the temps are also lower it also looks like it will work for a longer period. Other than that I am selling my cobs now, I am not really happy. The mars and many burples are not the best quality, my mars lasted 1 year and then started to fail (already had to fix it 3 times and paid under 40 bucks each time), its been 3 years running and still works better than my new cobs, but understand that the 900w mars was not even close to 900w, it still got me around half a kilo after 3 month anyway, with the cobs only got 250grams and it was advertised as a 600w hps replace (not even close).
So to end this, if you can DIY go for it, its super easy and I believe that with 9 cobs I might get what I can achieve with the burple but still not sure why I dont get nice phenos with white light as with purple ones. I will keep using burples as main one and add cobs that I will build.
To compare lights I used the same amount of plants, same seeds, same soil, same nutes, did everything the same way with both. In my country is legal to grow, here we have growshops in every corner, used to live in canada and they are not even close to be as in here where everyone grows (no coffee shops here because of that).
Good luck to everyone, I dont work for any company but I know many of you do, bye.