I think the least expensive bottle of it is $15 or so, so it's not a fortune if you don't like it. It's absolutely not constipating. I personally got good results with iron glycinate (didn't really know I was anemic, tests were "borderlilne" acc. to my indifferent GP, until I felt tons better after taking it).
The thing is, iron doesn't make me constipated. Last time I tried it, I was constipated to start with and the iron gave me unbelievable cramping, D and gas.