Pavel wrote:
"""We're trying to put too much information into it. That would never
work. Slogans are about emotions, not about facts. They should invoke
certain feeling in reader/watcher/listener attached to the rest of
message that contains facts. It may also provoke curiosity to learn
more about product."""

This is worth rereading. A comma-delimited list of positive
adjectives such as "The powerful, compact, reliable Open Source
Database" does not make a catchy slogan, but an unrememberable
"mouthful". It's been mentioned that the Coca-Cola slogan is
"Delicious, Refreshing, Fun", but despite having resided in
Coca-Cola's heartland all my life and having encountered that slogan
on numerous occasions, I didn't remember it. And for any (short) list
of positive database-related adjectives you can think of, every other
competitor in the database market is going to make the same claims.

A slogan that the target audience can't remember after just one or two
exposures is deprived of its impact. The most memorable slogans embed
a "jingle" in the target's mind that keeps coming back unbidden,
whereas most are too complex or too banal to remember. I don't know
about you, but I find it much easier to remember complete phrases than
comma-delimited lists of positive adjectives. For example, the
slogans I can remember off the top of my head in a few seconds are:
"Do the Dew"
"Where do you want to go today?"
"I can't believe it's not butter!"
"It's so easy, no wonder it's number one!"
"Diamonds are forever"

And while I'm whining, let me implore you not to include the words
"free" or "freedom" in Firebird's slogan. Whenever a product claims
to be "free", I think "What's the catch?", while "freedom" is usually
bandied about by those who have ulterior motives or are appealing to
nationalistic zeal (think "freedom fries"). In the US, at least,
decades of sleazy advertising and political maneuver have made "free"
evocative of "cheaply made" and "hidden clause", while "freedom"
evokes "the reactionary exploitation of fear".

An example of the type of Firebird slogan I could remember is "The
plug and play database". That slogan is arguably flawed because it
doesn't make the point that Firebird is more capable than the most
plug-and-play databases (e.g., SQLite), but it's a complete phrase
that highlights Firebird's most unique strength relative to the
databases perceived as its primary competitors (PostgreSQL and MySQL).
Notably, "The plug and play database" doesn't include any technical
jargon, so it's unlikely to cause a negative gut reaction among the
nontechnical types who make strategic decisions.