Neither are so expensive to me that it's a huge issue.
By my rough quick calculations look like:
A set of three 1qt Floras is about ~40$ range give or take. A 2.2lb bag of Maxi is 12-15$ and most likely you're using no more than 7g per gallon, making it good for 142 gallons of feed, making it 10 cents or less per gallon of feed water. Even if you're using both Gro & Bloom or just Bloom the pricing wouldn't change since you're using the same amount per feeding of either.
Trio is ~15ml per feeding per gallon (obviously differs based on how much you can feed at any given time), and the math works out to 189 gallons with all three quart bottles (assuming you'd use the same of each, which of course you wouldn't, something would run out first), so roughly 20 cents per gallon of feed.
I have a feeling (without calculating the sliding scale of the Trio's different mixes across a single grow and/or multiple grows) that the Maxi is probably cheaper on a per-use level.
It's a HELL of a lot easier to administer, given I was measuring the ratios of nutrients individually for gallon jugs of water with syringes, then also doing the pH balancing, etc. Way easier for me to weigh the amount and dump that little pile in each jug.
I'm hoping it also adds to my grow consistency since I always seemed to time things wrong and end up deficient in week 3 of flower and have to fight back from it.
MaxiGrow & MaxiBloom are also a bit easier to handle in the mixing. You can figure pretty reliably what the PPM per gram are, then measure the amount you're looking to feed based upon the PPM per G. From my testing 1g of MaxiBloom ended up being 90-100ppm or so.