if ur used to think that 400-600w hps on 4x4 it is enough then +300w is a big jump and if u then think again u want led to lower costs and increase PAR for same space coverage its an issue isnt it?
Led will not lower costs unless it has a higher efficiency than the light your comparing and that really has little to do with sizing. At 1900+ umoles I think it's one of the most powerful lights available.
I wish other companies listed specific numbers like this. Would make comparing facts a lot easier on make light choices. A Mars watt and a Amare watt are 2 totally different thing.