I've only played a few games with the lance Dauntless' I have running around but I thought they were pretty good for 110 odd points. I'd second the comment about pairing them with their escort class equivalents.
It's a bit of a concern that they have to turn head-on to target with their primary weapons given a single shield and 5+ prow armour so I tend to use them more as a skirmisher or escort chaser.
3 firestorms may be potentially a little more resilient (smaller targets, more turrets, multiple 'effective' shields) and slightly more maneuverable but I like the idea of a Dauntless filling up a required cruiser slot for purposes of fielding the heavy hitters. Put it this way: you can get 3 Dauntless cruisers and a retribution (or emperor if that floats your boat) for under 700 points. Could be fun...
![Tongue :P](http://www.specialist-arms.com/forum/Smileys/default/tongue.gif)
Cheers,
LDTM