you can read thread about that by search this forum, and then you can decide which one is better for you!
I wouldn't call the stuff that I get with auto social poster in my niche anything of real quality - I wouldn't want it on a blog I usually write myself. It seems fine for auto blogs, but in that case there isn't really much reason to purchase it, as you can already use RSS feeds and Syndicate Kahuna for free.
If anything I'd download an older cracked version and try it out before plunking down cash for it.
Disappointing that you say that as I think I was more or less leaning towards ASP.
I guess the best way is to do it on your own.