I'm putting in some LakeVues as we speak. They are a bit lighter, the install is a bit easier, covering them, should you want to is really easy. They install in such a way that you can still use your factory seats, at least I can use mine in the 185. So if I am actually taking somebody in the back for a long ride I can go to the comfy seats in a few minutes and a logbook entry. In reality, I almost never take anybody in the rear seats. Then again you never know, zombies could be chasing folks down the runway and need a lift…
I use a combination of cargo plates with the push on clips and the clamp onto the seat rail. The push on clips are 100# and the seat clamps are 300# tie downs. One thing I really like about the LakeVue mount is the addition of more standard seat track. I have a seat rail clamp that has a bicycle fork mount on it, so I can mount my bike upright with the front wheel removed and it is über stable. Kind of a niche requirement for sure, but import to me.
The choice of the two is really one of aesthetics and cost. They both function virtually the same, weight is similar, function is similar. I spent some time looking at both installs, the Dr. in the hanger next tome had LakeVues and I looked at others that had Altee's. I liked how the Doc's came out better, from an appearance point of view (he had a dude in Prescott make some really nice covers). He claims they are very comfortable on trips from Flagstaff to Idaho, where he has a ranch. He is kind of picky about his aircraft, he has 5, including an Beaver and an Albatross. I like the ability to use my factory seats, the seat rail clamp options and ease of installation and removal. Oh, one other item, Denny actually has them in stock, so you get them in a few days and don't have to wait for them to be built. As wonderful as Altee's company is, due to Alaska's inventory tax laws, they keep very little in stock.
Tell your mechanic that if he pays the $400, you'll switch.