try it, get a free demo of n track or what ever you want... try it
you will find lots of sound card issues, interface issues, latency issues, the latency is the worst.....too much to deal with and your going to spend about the same amount on the interface anyway... the mr8 records and punches in seamlessly.... very hard to do recording on the pc... you need a real powerhouse of a computer, doing it this way an old pc with win 98 will work.....
get the best of both worlds, most professional sounding recordings from a home studio i have heard, while many do well with the bigger units, cost is a big issue for me with the mr 8 and n track and the pc i altready have i have a unlimited number of recording and effects , limiters compressors, eq and MASTERING options....
nothing wrong with mixing down on the mr8 and learing to record.... after you get to a certain point, you are goin gto want better sounding recordings...