How good a student is Draco?

[Wanda Sherratt]

No: HPFGUIDX 47289

I was wondering if Snape favours Draco purely because of his family 
connections, or because he sees in him a resemblance to himself at 
that age, or if perhaps he might reasonably be good at Potions?  I 
know at the beginning of CoS Lucius Malfoy makes a remark about 
Draco having poor grades, but I wonder if we can really take that at 
face value.  Lucius is one of those cold, punishing fathers, and he 
may be the sort who would be dissatisfied no matter what Draco 
does.  He mentions that Hermione beat Draco on every exam, but 
compared to Hermione, practically anyone would come off badly.  Are 
there any other passages that give a clear idea of whether Draco is 
a good or a poor student?

Wanda