I have been experimenting with the Athena 6 Body BOM enabled. You need to right click touch Mid body area to activate BOM on body and right click touch head to activate it on the head. DO not have Body or Full alpha on when activating BOM. It doesn't need the alpha on. The main benefit of the BOM (bakes on Mesh) Avi is that you can wear system clothes and some make ups and skins with BOM Body along with Mesh layered on top. As you can see from the pictures below, I have on regular non mesh avi top, tights,socks, Mesh Jacket and Mesh Shorts and Mesh Boots on. I did need to use the alpha hud that comes with the 6 BOM Body to hide arms so it doesn't go through jacket and it covered the area with the system sleeve under it so it worked well layering.
A lot of the older skins and make ups don't work with the new BOM Body. Just use the Makeups given with the BOM Body or in the separate BOM Boxes of skins and makeups etc.
The initial set up can be overwhelming and it takes time to get the right shape and eyebrows and lipstick and stuff you want to get certain looks. I suggest setting up a few nude looks with the body and head combinations as outfits themselves. This way you can easily pick a look and just layer on clothes.
The make up huds that came with say Catwa Head and other lipstick huds don't work with BOM activated body but they will work if you use it as a regular Bento body and head combo. For that you need to wear the alpha full body one and it becomes a non BOM regular bento avi. That is best if you don't care to layer the system avi clothes with it just use it as a regular mesh body. As of writing this post there is no male BOM Body yet but I seen someone working on it probably won't be long till it comes out.
I noticed for some people coming into our grid which is BOM and Animesh enabled, some BOM Body people go white, some rez fine. This may depend on your set up or what happens with server communications between other grid and ours. Not sure how that fixes other then relogging maybe? It is too soon to tell. Also, one really cool thing I found is that when I used the Hand Animator to make hands look natural on the Bento body it stayed as it should not spread out like a fan. And even after relogging it stayed that way so that is a huge benefit. Also, on the hypergrid (only tested one place), it didn't seem to affect the alpha hiding or mess up anything coming back to grid which usually seems to happen with older mesh bodies.
*Old physics don't seem to work right with BOM just to let you know you have to relog and maybe remove and add them again seems to get whacky*
*Disclaimer: I certainly have not much scripting knowledge so I can't help with fixing anything that needs fixing scripting wise. Also, I picked this stuff up from hypergrid so I am not claiming any rights to the objects provided* (Aqua Tranquility)
*Bottom Line it can be a pain in the ass to set up but it can be interesting and gives you more customizable options.*