I was in the same boat as you recently and i want to share what i got and why i got it...
Was initially planning on getting 3 or 4 COB's or an HLG QB for my 2x4 tent but my budget was limited so i ended up buying the Mars Hydro SP-250. I was a bit hesitant to go with the DIY quantum boards as i really don't like how everything is exposed on them(diodes, wiring etc.). The SP-250 is IP-65 water splash certified, has some sort of special rubbery layer over the diodes to protect them from water/humidity. And it's also plug and play which is another thing i like. That said i stilll wasn't convinced until i saw some reviews on it that confirmed how efficient the light is, the impressive results finally convinced me to pull the trigger.
I gotta say i LOVE this light, it's so damn bright and the coverage is absolutely perfect for the tent. This light is something else, still does
well over 400 PAR at 30", it's white light QB technology so the canopy penetration is really deep. No more popcorn buds on lower branches for me, everything turns into very solid nugs and the frost level is insane compared to my previous outdoor grows(got a greenhouse i use during summer). For 250 bucks you won't get anything better, you have to spend alot more to match or exceed this. Or in other words, you'd have to get 4 60 watt COBs or something like the HLG 260 watt XL kit to outperform the SP-250(and even then not by much), i'll let you figure out the cost on that. If it's bang for your buck you are looking for, nothing beats the new Mars Hydro TS and SP ligths imo.
This is the coverage Migro was able to get in a 2x4 simulated tent area with reflective mylar walls, light was pulling 235 watts at the wall and i believe the hanging height was 16".
Not bad huh ?
If you want the latest and most efficient and don't mind paying extra(about 100 bucks more) and don't mind some DIY i'd step up to the HLG R spec kits or something like that, more efficent then any COB with superior spectrum, this would have probably been the route i would have taken if i had a bigger budget. Again like i said, not too excited about DIY or exposed boards. I do prefer pre-assembled COB's from that perspective.
As for the tent, i again went with Mars Hydro. I could not find any other tents with 1680D diamond mylar reflective interior for even close to the same price. The only complaint i'd have about that was the shipping on the tent was a bit high but that varies depending on the region you are in(i am in EU).
Hope this helps you out a bit.