It actually makes you worse for having taken it.
Requires: Combat Casting, Combat Expertise, Dodge, and Weapon Focus. Three poor feats.
You can be a Bard 7/Bladesinger 3 at most. Compared to a Bard 10, you gain +1 BaB and +1 to Ref and Will saves. 2 more hp, on average.
You loose 12 skill points, access to many skills, Inspire Courage +2, Inspire Greatness, and one caster level.
That last one's kinda bad, as it cuts you out of 4th level spells. Dimension Door, Freedom of Movement, Greater Invisibility...
Ok, but maybe the abilities make up for it. Let's see... you gain a dodge bonus to AC of your class level, limited by your Int bonus. Unfortunately, you have to have a longsword or rapier in one hand and nothing in your other hand. This locks you into a weak fighting style and really cuts down your melee damage output in favor of a bit more survivability
It sucked when it was on the Duelist prestige class and it sucks here.
The other thing you get is the ability to take 10 on Concentration checks to cast defensively. This is not necessary. The skill check to succeed on casting lower level spells is trivial to make at level 10. 13 ranks and a +4 Con bonus mean that your result is a 18 if you roll a 1. This is enough to automatically pass the check to cast level 3 spells.
Basically, the return on your investment is horrible.