Good question. I would think it depends on what I am getting in terms of added functionality for the extra weight. If I were a firewood dealer then 150 lbs would be a fair trade off for the extra wood I could carry as the limitation on load size with firewood is clamping not lift capacity. If I were only interested in moving stumps or logs then IMO all the lost lift capacity is regrettable as the second lid doesn't add anything. For brush it is a toss up as the second lid doesn't add much but also doesn't detract from load capacity as brush just isn't dense enough to challenge lift capacity.
And, I have to come back to the simple fact that regardless of weight penalty significance, dual lid grapples cost more and are beneficial in only limited settings. A narrow single is just fine for the great majority of tasks that a private landowner might need a grapple for.
No doubt for a specific task one type or the other could have an edge at the expense of other tasks. From what I read on here the grapple is purchased as a multi tool and it certainly is for my uses. To me greater versatility of a dual lid is more important than the last few pounds of lift. If weight is an issue I'll simply make an extra round. No big deal.
Has anyone thought of the limits on the front axle of the tractor on some of these super heavy loads? I know the weight of the grapple is unimportant in that respect its the total load that counts. I'm just thinking of the front axle rating and is it being exceeded with some of these big grabs?
Cost wise its a one time purchase. Get the one you want. Has anyone worn out a Wicked? Where is the oldest known Wicked?
I agree the average user could get by with a narrow single and save some money.