Yep, the event is a frikking lottery, and even if spending your lanterns wisely you are not guaranteed to win, even if a single frikking upgrade. I am on the brighter side this event, winning a gong for both worlds (two in first in fact) and two other upgrades in each world as well, but not close enough to getting at least a full set upgrade. The problem here is that you only need to spend lanterns on 20-flower chest (60 or 65 lanterns apiece), the other chests are worse by all means. And, given the total amount of lanterns acquireable, you will NOT get the second grand prize without spending diamonds, and at a price of 12.5d per flower at best (not counting sales) the price to reach the second grand prize, which is by the way a MERE reno kit that you can get elsewhere, albeit at a chance, reaches a thousand dimonds. Getting the third prize is plain impossible without paying.
Now, on the credit side. The quests so far (43) required me to do 10 sectors, 2 techs (with alt prices tho), 1 new and 1 old province, a ton of goods and ~20 bought FPs (lost count). As a consequence, even with careful planning I would have to use 2 full provinces (3 in Iron, as there are some with less than 5 sectors) solely on event quests. For me, this price is too heavy compared to what benefits you can receive from the event rewards, with just a little below average luck, that happens way too often here, especially if counting dropped DCs due to the need to conserve opened provinces.