hello tony1
i have a friend that purchased the sp2 and we started comparing units, i also really liked the c-series cosmetics which has a much thicker face plate and the display is much nicer.
but what really lead me to purchase the sp2 was the sound that was coming out of the unit tony i was thinking of upgrading from the 1.7 to the sp2 but i got a really good deal on a sp2 that i could not pass up. like i mention in my post the unit is awesome the sound is just much cleaner and instruments just come out at me i wasn't' getting that from the 1.7 also the 1.7 to me is a warmer pre/pro from the sp2 which warm is good but when i heard the sp2 in my friends house it was just much better.
remember the 1.7 has the Motorola 56367 dsp chip the sp2 has the new ti aureus chip also it has the bp26 analog pre/pro in it which makes the 2-channel bypass sound great.
so that's what made me upgrade to the sp2, know listen i think you will benefit a great deal on upgrading your 1.7 to the sp2 . i didn't do it because I'm meticulous.
good luck on what ever decision you make, also if you upgrade let me know what your hearing and tell me if you here a difference.
chip1