From astrology.com (must I beware of overindulgence in such websites?)
I like the part about charm and charisma and think it is very true.

Sagittarius and Sagittarius
When two Sagittarians join together in a love match, the truth-loving natures 
makes theirs a near perfect relationship. This couple views the world around 
them with an educated eye and both share an intense hunger for more 
knowledge. They will engage one another in pleasant conversation and 
banter that challenges and tickles the mind.  An occasional hotheaded dispute 
can erupt in the Sagittarius-Sagittarius relationship, when one fact-fanatic 
Sag 
partner carries things a little too far. Easygoing and independent, these two 
are 
compatible when it comes to balancing personal interests. They've never known 
jealousy, and each partner keeps busy with personal projects when not with 
their 
lover. When they are together, however, they do all they can toward pleasing 
their partner and satiating common interests.  Although they are adaptable 
and 
modern, they can, at times, fly off the handle. However, it is not in the 
Archer's 
nature to hold a grudge or let disagreements fester very long. 

Sagittarius is ruled by the Planet Jupiter (Luck). Expansion is the key word 
here; 
as both partners enjoy the acquisition of knowledge, they will carry over 
exciting 
ideas into their relationship. They must be mindful of over-indulgences, as 
such 
gluttony will only distract them. Their charm and charisma make them a very 
pleasant couple not only to one another, but the entire crowd.