Please Recommend a 1 piece tub + shower in $400-900 price range

[Chris Jay]

I am doing new construction for properties that I would like to rent and hold on to for quite a while. I am looking for a recommendation for a durable 1 piece shower with tub units that will last a long time and not crack/leak. Any suggestions? Right now I am looking at 

Aker CM-60 fiberglass for around $420

Aker ACCTS-3360 acrylic for around $800

Delta 226032AL00 "Acrylic" $500 (although I've heard that it is just an acrylic layer over other material).

Any suggestions of different units or recommendations of things I should be avoiding?