Twitter profile: Personal photo vs brand graphic image

[sftravel]

We are promoting our company on twitter, and currently using a high quality brand graphic image.  We see others who use the personal photo of "evangalist" who manages the twitter account.  Any advice on what works best here to encourage user engagement?  A more generic "brand" identity graphic versus a real person's photo?

Of course this is in conjunction with doing all of the other good Twitter things, but curious what folks recommend on the profile image.

[Syed1]

More info on the size of your company and also the industry and what you expect from Twitter would help.
Personally, I don't think there is any harm in maintaining both accounts.

Have employees create their own Twitter accounts and use their Firstname-YourBrand (e.g. Craig-SEOMoz) as handles - that way it has a personal feel but it also helps in branding each time other viewers look at their profiles/tweets.

[GardenBeet]

If you have the resources and you are a well known brand its great to have both the generic and the real person.

But if your brand is relatively unknown, resources are limited and you are wishing to promote your company I would be using the logo. I use my company logo for Garden Beet. Many in my tweet network have got to know me over time and use my name on tweets as well. That has its own set of problems and benefits.

Nevertheless it loads easier to create connection with a person than a logo. I know I prefer a person to a logo - but that is not meeting my longer term goal of trying to get my brand - Garden Beet -  known.