Buy an old website or develop something brand new?

For a couple of days now I'm contemplating if I should buy an already established website or develop a brand new website myself and start from scratch?

Some of the benefits I find in buying an already established website:

• The boring part if already done - I tend to lose myself in the details when I first start a new project, this is why so few of my projects actually become a reality. I tend to abandon them half way thru;
  
• The only thing it probably needs is fresh content;
  
• The amount of work put into it by webmaster who sells is probably way bigger from a value point of view compared with actual prices the website is selling at;
  
• It may have some traffic - You won't get any with a fresh new site;
  
• It may have some authority or backlink - You need to start building them with a new website.
  

Some of the negative aspects I find about buying an already established website:

• There are strong chances you are buying someone else's mess. Let's face it if the website was doing well it wouldn't be on sale in the first place;
  
• The website's niche may not have money making potential, hence this is why the website is up for sale;
  
• If you are not a coder you can't evaluate any potential bugs that are present in the website;
  
• Buying a website is messy, the domain needs to be transferred and getting everything hosted on your hosting company could be a pain in the ass;
  
• Because this is not your original project, your "baby" so to speak, you may find that you like enthusiasm working on your new acquisition, therefore, the project may be abandoned or sold again to another webmaster
  

So here are the hard facts from my point of view. Which would you choose? Do it yourself or buy an established website?