I have tried Many Link Building services in the past and only 1 has proven to be successful. You can PM me for more details, or check out my Signature
its best that you do your own link building. if your sites falls into wrong hands, then you are in trouble. i have seen it happening a lot. do some research on how to build links, what are possible ways, and put togatjer a strategy. i know it will take time, but it will serve you well in the long run
...and I've seen people take your advice and make the same mistake and that's better? Surely this is the wrong additude to advise someone... you advise them to avoid outsourcing because they may get the wrong agent... what if they read the wrong resource and do worse on how to build links? How many businesses don't outsource anything? How many business owners risk hiring the wrong employee but have to hire anyway? Better advice to offer... "Make sure you don't hire the first person that comes along, get quotes from a variety of firms." "Get references and call them." "Have clearly defined goals and objectives for the service provider to achieve." Once you have all the information "Get a second opinion". ...The learning curve on "rersearching for the right link developer" is significantly less time consuming than "researching everything for DIY" and the outsource link developer is less risky than trying to be your own service provider... ignorance in link development is worse than being ignorant about your link development service provider. Lastly, the people that got screwed by a link developer... likely didn't do any research "what so ever" and that's where the problem lies.
Learn a lot from here.. and try to build your own link building methods.. do n't rely on SEO companies.. they may charge very heavily for these services..
This also assumes your time isn't valuable... While you can't trust "anyone" at face value to protect your interests and serve you ahead of themselves... there are many advantages that "most" link developers share over doing-it-yourself. 1. They tend to be already in the know what to avoid which is about 75% of your time "wasted" on chasing links that do nothing. 2. They tend to have their own network of domains to start their services off with that the DIY doesn't have access to. 3. They tend to have a many partnerships with others in the industry that the DIY doesn't have access to. 4. They tend to have invested in tools that are time savers thus higher productivity. If your business "isn't link development" we can assume you got to waste some hours running your business which means your link developing learning curve is much long and so is your fruition... If you add up are your "costs" to learn and to do that as much as paying heavily to someone else and the time your lose running your business makes that even more "costly." Obviously if you don't run a business... you have a hobby site; your time is free and isn't a factor.
It would be best that you read and learn on your own before you hire someone or a team to handle your site. When you have a grasp of the different ways you can build up your links, you can then decide what you need. Some companies just slap you on the face with seo mumbo jumbo and expect you to pay a horrendous amount for services that you don't need. To make it worse, the results are so minimal it's not even noticeable. I'm not generalizing, there are people who make an honest living out of this; you just have to figure out how they can work for you.