Juan Pablo 809-882-7448 installed gutters on my terrace in my condo.
He is a good guy with reasonable prices and although you have to keep an eye on the workers the end results were good.(He also installed a new metal door for me).
I have used him twice and would use him again.
You might want to try Julio Genao, Proprietario, 809 261 3882 or cel 809 232 8703.
En la entrada del Padre Granero, Calle Principal No 12
He made and installed metal gutters for our house here and I know of a number of other places he has installed them. Not the cheapest around but reliable and they have lasted well. He can make them in the colour (painted) you want and they are in general made out of thin galvanised steel sheet. He may make them in other metals but I dont know about that for sure.