Is link exchange a reliable source to get back links?

[semvibe]

I read a latest post on seomoz that _“Do not buy or exchange link with anyone who contacts you. This is completely against Google's policies and if they were to find out, you could be penalized."  So I went through Google's ''Link Schemes''  and found that ''Excessive link exchanging ("Link to me and I'll link to you")''  can negatively impact a site's ranking . _

So is it the ''excessive'' link exchanging that can cause a negative impact? Exchanging links with good quality, cached sites (without excessive doing) can do good or bad? Can anyone please explain to me in detail?

[SanketPatel]

Ya,link exchange is harmful for your site and it can also negatively impact on site's ranking. As  Keri Said " Do keep in mind that it is against Google's guidelines to buy links for the purposes of passing page rank. "

According to my experience One-way link gives more link juice then link exchange. In the past same question was asked you can get more ideas from these answers about the link exchange.  http://www.seomoz.org/q/are-link-exchange-a-bad-idea