I'm not a big fan of advertising for most firms. That's because there are so many other things a firm can do first to effectively gain clients, but haven't tried enough of. So, until they've done other more effective things, i.e., face-to-face kinds of business development, advertising is a waste of money IMHO. And, it could backfire. More on that in a moment.
Furthermore, when the law firm is doing the "institutional" kinds of things, like brochures, sponsorships, websites or other kinds of advertising, partners think they don't have to do the "personal" face-to-face stuff. They just opt out, don't get individually involved. However, if you are going to advertise, then at least don't raise expectations of "quality service", or "client-centric" or "concentrate on personal attention", "prompt service", etc., etc. in your ad, and then not do it.
Seth Godin has a blog post that as usual is pretty much on target. He warns against promising things and then not delivering. He uses the examples of Delta saying that it is the "better airline, one that cares") or the bank that has "flexible people eager to bend the rules to help you succeed" (and then don't) which makes it worse by saying it in the first place.
Read more on LegalMarketingBlog.com.