I guess they are different enough to fill a niche.
I know mine with adapters can support 2 EVO's and the other things I mentioned before about the squared off barrel Shape.The bottom of the sidecar can collect what have you. I've owned a few claisens and they all died. The walls on the barrel feel thick and with few rounded corners as stress points to break on me. To think I had a vapor buddy all this time.
Each of your choices hones on a different function, if you think about it.
The vapefiend one resembles mine and @mom's. $50.00 if you must have it. Can't find it on ebay and DHgate ATM.
The planet vapes looks best for a carb setup especially the handle. I would examine the joint on it, if you plan on defying gravity with your setups. But could work fine with a log vape in the sidecar.
The Oregon is all about the airpath. Sturdy and under $40. but the carb is 10mm, Not the dimensions I had in mind tho. The top is 14mm. But a custom that was all 18mm would be the best of most of the offerings.
I'd trade off the barrel for the action for this.