Damn! I can't decide which one to buy.. 5P or DigiZoid FS ... I like the price and the settings of DigiZoid.. But considering the Arrow 5P because of it's better noise performance..
Depends on what your usage will be. Have never tried DigiZoid so I don't know much about its performance, but for Arrow 5, you might want to check out the 5N instead if your main use is with full size. If my memory serve me correctly, the 5P's bass boost is very much like the 3G's, which has 9db boost on level 1 and +18db for level 2.
When using the bass boost with my IEM, level 1 works pretty well and adds a deep punch, but level 2 can be over powering. Level 2 sound like a car with an oversized subwoofer in the trunk, and you can hear the bass distorting the some of the music. So level 2 with the 5P would only be useful with very specific genre of music (I tested with some bass heavy song, and it is too much) AND and bass light IEM.
When using the bass boost with my full size, level 1 works well on all 3 of my full size (especially with Low on bass freq), but level 2 was way too overpowering. It sounds like you are sitting in front of a subwoofer, and not in a good way. It also made the Alpha Prime distort pretty badly. I think level 2 is something I wouldn't use often with a full size. (Unless you are an EXTREME bass head that likes OVERPOWERING bass)
With the 5N, I believe the boost is +6db for level 1 and +9db for level 2, so it give you more to play with in terms of listenable bass. I would probably only recommend in the situation where you really want the super duper bass boost for IEM. (I only elected for the 5P because I pre-ordered and got the 5P upgrade for free)
The 5N should be exactly the same as 5P in all aspect, except for the double bass boost. So you'll be getting the same amp without the super duper bass....