People are more likely to remember bad things, its human nature. They are also more likely to share a bad experience with a total stranger to keep them from the same mistake than recommend something. There are entire companies built around positive word of mouth advertising of products and services (house party, bzzagent, repnation). I think the fact that big companies are willing to spend so much to get positive word of mouth shows how important it can be.

I personally talk up good or bad experiences and do it to alot of people I know both personally and professionally as I think sharing personal experience is helpful to others. I've done this about some products for decades. Many people do.

So while advertising and SEO are important to get it off the ground, once you get customers and are able to continue to impress them with good service, quick ticket turnaround time, etc you will give them reasons to keep spreading good things about you.

It may also be better in certain markets. I know that in small towns, where "everbody knows everybody" work of mouth would work wonderfully. You would need to be sure that there are no "bad experiences", because that would most definately be what is told if there is. Overwhelm your clients with the good and they will want to tell it!

Id agree word of mouth is the best it makes you feel good and also that feeling your are doing it right but cant always reley on word of mouth

Once you have a good client base, word of mouth will become a main part of your marketing.

incentives for refferals are always a good idea such as 3 referrals and get a free month - something like that card you get from the video store - rent there 8 times and get the 8th one free.

Word of mouth is a very good form of advertising. But the thing is when you have less clients it is very difficult to achieve. You will have to keep your patience and grow your business and over time word of mouth advertising will also grow along with your customer base. There is no short cut to success.