Hi Shell, sorry for the delay in replying and thanks for your comments.
Yes, I'm sure Google will be clever enough to reward quality comments that add value and not reward the obviously spammy ones.
You're so right about short term gains - I had one client who ignored my suggestions completely and decided to do things his own way. He was full of himself when his rankings had increased dramatically after two months of using automated backlink software.
A few months later his site was penalised and he was back on the phone begging for help!