Viking liferaft

[Alls Well]

I am wanting to purchase a Viking 4ukl 4 person liferaft to store in a cradle, mounted on my stern rail vertically.
Speaking with my local raft distributer, he recommended against Viking for this. He has had several Viking life rafts, mounted in this fashion, that have had rot issues when the 3 year service was due. And Viking will not warranty their raft for this issue. For this reason, he has stopped carrying Viking. He also said that the other major liferaft companies do not make a unit that will mount on a stern rail in the vertical or horizontal position. They are made only to mount flat.
Has any body had similar problems with Viking? Would you not recommend them?
Thanks for your help