Long story short...with the cantilever system you will allow more wheel travel. This is granted through a smaller coilover that is in a safer location through the geometry of its design. The Bolton coilover is longer, but due to its vertical design there is less wheel travel and it is left more exposed to impact just like a stock shock.
What StrizzyChris says is mostly true. The EVO lever does not necessarily provide more wheel travel than a traditional vertical coilover setup, what it does provide is up to 14" of usable wheel travel by using a much short horizontally mounted coilover, with the mechanical advantage of the cantilever system making up for the extra up and down travel that you would get with a similar and much longer vertical mounted coilover. A traditional vertical mounted coilover system can give 14"-36", or even more, wheel travel. But that comes at an expense I will cover below.
The true advantages to running the EVO Lever is that the 14" of usable wheel travel is gained by not having to cut into the cab of the jeep to allow room for the really long coilovers to be mounted. The EVO Lever allows you to have a sealed, dust, free, air conditioned/heated cab, because the coilovers mount horizontally and stay on the outside of the body. If the rear of the JK was longer, in theory you could mount even longer coilovers to the EVO Lever and achieve even more usable travel. But there is only so much property behind the axle to occupy. By the way 14" of wheel travel is a hell of a lot for a daily driver and 14" of travel does not mean the shock is only 14" long, the shock is actually a lot longer. Now if you want to gain 14" of wheel travel using a traditional vertical setup, the coilovers have to go somewhere. You can't really go below the axle any further than the stock shock brackets because you are asking for things to get damaged and you are not gaining any additional travel by attaching a coilover to a longer bracket. There is only one other option, to go up and through the floor into the cab with fabricated shock towers that occupy room in the cargo area. In one of the pictures above, you can see the manufacturer attempts to cant/lean the coilovers inward and backward to fit their coilover length under the jeep and avoid having to cut into the floor of the rig. By doing this canting and leaning, they have actually lost some of the shocks travel, so although the coilover may be capable of 14" of travel, their system design has wasted and lost some of the travel by poor shock positioning. This is where the genius of the EVO Lever wins every time. So can another system give the same amount or more of travel, sure, but you will have to have coilovers going up somwhere into the cab. In my pictures you can see what 14" of usable travel looks like with the EVO Lever, it is a whole bunch and it means your tires fill holes and stick to rocks which means you have traction