I am thinking of using a Acrylic Enamel made by Hawthorn Rayflex (seen on e-bay for 34.99 gal
they also have a Acrylic Lacquer for 79.00 gal)

Has anyone used this paint and what were the results?

I have test sprayed and the paint flows really well but I still have concerns over durability, exposure to UV Rays ect.. and the fact it cheap paint.

I've never used the stuff so I may be wrong here but you usually get what you pay for when it comes to topcoats. Enamel is seldom used in my area for anything except heavy equipment etc. The durability of urethanes just can't be beat IMO.