Wondering whether anyone else is seeing similar experiences with link building and website ranking...

About a year ago if I had a review in say position 7 on page 1 I could do a blast with SEnuke and in a couple of days my site would pop up to no.1, now it seems that my review site just disappears from the rankings altogether for a few days up to a week before it returns...

Seems like lately if I get my on page SEO down perfectly then I'm better off not doing any link building (on the low comp phrases / reviews etc) because the site ranks without any linking.... if I do link build I seem to get penalized for a few days before being rewarded which although is good in the long run, it's bad initially because I'll lose my ranking for a few days which means I'll miss out on the commissions for upcoming launches!