As Search Engine Expert I believe all SEO companies are quite aware by now of what is ethical and unethical. This subject is as old as internet forums.
With 10 years of experience and a PhD in E-Business Marketing, I am convinced that even though "in house optimizers" are a basic and known way of implementing optimization, it is a clear reality that under the right SEO company ,results are more than significantly excellent as well as a great cost reduction for companies.
I've met innumerous so called "in house experts" which I can regard more as spammers than anything else. Many of them survive with forums like this one as a way to earn a piece of the industry. Many companies don't know this and they end up asking their own technicians (which are NOT experts in the SEO field) and webmasters about what should be the correct SEO practice to implement for the company. As a simple and logic advice: "Let specialists deal with their own specialty". Webmasters and company technicians are not necesarily SEO experts or SEO marketing specialists. The same way you trust your dentist to deal with your teeth... Let SEO companies deal with SEO issues!
Search Engine marketing is a fast paced, constantly changing industry. My experience and that of many consultants in the United States is that to guarantee the best results... keep it basic! Outsource your SEO solutions and let SEO companies deal with SEO work.

Logic falls under it's own weight...Many SEO companies have a team of experts, consultants and technicians whose work is to study, analyze, research and deliver relevant results to each individual company. With this, I am trying to say...As much as I would like to let my 19 year old university technical web students deal with SEO work, I believe search engine marketing should be dealt by SEO companies.

In terms of ethical or unethical...as Search Engines are neutral to SEO companies, make sure search engine guidelines compliances are deliver in separate sheets, whereby stating that they comply with the rules and regulations of each individual search engine. Ask for technical specifications and clear patterns of communications.

I personally had the privilege of meeting Jajja's CTO at the last Online Marketing Conference in England (Search Engine Strategies).  I have to admit that Jajja's CTO is among the best in Europe, even perhaps the US.  I believe Jajja is one of the largest SEO's in Europe with perhaps the largest technical staff in Eastern, Central and Northern Europe.  Their SEO techniques are quite unique and innovative like that of many well reknowned Scandinavian IT companies. From clients I know in the industry and professionals within the SEO Field, Jajja is by far an Ethical SEO company.

This can be said for most industries can it not ? you must separate the cowboys from the Indians. I think that most company's can now make their own decisions and if they want to go with the cheaper option most of the time they will get stung. I have found like you that even the so called big boys in the industry will use some awful techniques to get their pages ranked. The only way they could really sort this out is to proper regulate the industry.
Ben Norman

Innovative? Creating door way pages, is that innovative? Not really. Rather a black hat technique as they just stopped with. They been banned from google before and might be it again.

About their staff. Yes, the firm is pretty large. But it's full of salesmen, not SEO's. On every SEO you will find maybe 100 salesmen.. go figure what that means.