Nutrafin and Salifert make good ones too. I used to have an API Master kit but the nitrate readings were unreliable. Never had a problem with my Nutrafin kit. And no, don't use a marine test kit for freshwater tanks.
i use these Jungle test strips- for fresh and salt water. they are accurate and test for PH, nitrate, nitrite, hardness,alkalinity! it is about 11$ for a bottle (25 test strips) but i must say that it is worth it!
**they do have new packaging so its the same name but different colors** and does not include chlorine test pad any more, just noticed that.