Hi from pitch black 3 degrees C York UK 
A friend of mine wants a website with a cms and i was thinking about jumping into wordpress but before i do i have these concerns.
Any insights welcome
Unless your friend wants to pay for extras, a .wordpress.com hosted site is a bad idea for a CMS. You cannot edit any of the themes unless you pay. I haven’t ventured in WP as a CMS really, but it seems like you need to edit a theme. Or at least have custom pages, which to my knowledge you cannot do under the free version. Anything else, I wouldn’t take credit if I were you.
Damn my quest for offering a website driven by CMS that my brains could handle hits the buffers once again 
If you get a domain, you can certainly setup wp to be a CMS. There are tutorials how to do it, even ones that have videos. Knowledge of PHP will be needed.
If you are going to design for small businesses, I would just pay the $5 a month (or less) for a host and install WordPress on the server. I personally love using WordPress for small businesses, it’s perfect. Most small businesses don’t really need a “true” CMS and WordPress works beautifully and gives the client the option to do their own content updates. The amount of support and info you can find online is excellent. There is a lot of info on using WordPress as a CMS too. Good luck!
You might want to take a look at modx cms. You don’t need to know php, the learning curve is minimal, and the sites turn out very nicely.
Good day, it’s been my experience that wordpress.com sites do not rank (or at least do not keep their organic ranking).
If you are helping small businesses in order to get them more business I would steer away from WP.com.
IMHO. Bill
I work on a website and we rank front page for some VERY competitive keywords with our Wordpress site. The outputted HTML can be just as good as any other site, it’s all on the developer.
I personally love using Wordpress as a CMS (when the content is blog/article-esque). It’s fairly simple and has pretty good results. It does take some knowledge to do some advanced stuff, but you learn that as you go.
If you want to use it though, host it on your own server (whether it’s shared or something else).
A site with a independent domain like www.mysite.com is much better than .wordpress.com
Now domain is not expensive and many hosting service with cpanel including wordpress and other cms scripts that you can install them with one click.
Good luck.
If you do go with WordPress, I’d definitely go with the self-hosted version (wordpress.org). The new version of WordPress is designed to simplify managing multiple sites with just one installation. What you should be aware of when using WordPress is making sure that your sites are secure. Because of WordPress’ popularity, it’s a much loved target by hackers. There are plenty resources on how to secure your WordPress installation. I really like the book, “Digging into WordPress”. It’s not only a good book for starters but also has some solid information on the matter, if I recall correctly.
Since you recommended this book previously, I bought and read it. It is a great book. I guess since I’m a “beginner” in WP, I thought that it was really easy to follow. And I did think the beginners could follow it too. But I confess that I’ve read SP WP book first, so maybe that’s the reason. SP’s book is more about creating child themes based on thematic, if possible
I agree. I started my web development business by using Wordpres.org as a self-hosted solution. After I gathered the requirements from my clients, I just use wordpress.org as the CMS and build the site for my clients. I would say that wordpress is one of the best cms for most non-web savvy clients to learn how to add their own content =)
Like the free blogger platform version, a .wordpress.com account also has the potential to just disappear with no warning since you don’t actually own it. So it’s a no no for venturing into online business.