Flora Nova is practically the same as the other nutrients mentioned, just more highly concentrated -- and proportionally more expensive. You don't save money by using Flora Nova, but you have to buy less often.
If you can get it really "cheap", you pay maybe $20 per L, which is barely on par with Jack's or Masterblend (both quite expensive as well). However, Jack's/Masterblend (or some affordable equivalent) gives you the option to steer the N:K ratio throughout the grow, and their formulas come with Ca+Mg, which is not the case with Flora Nova (GH recommends CalMag).
I guess if you don't need Ca/Mg and don't grow a lot, Flora Nova can be quite convenient, but it does not look like a silver bullet that blows anything else out of the water.