Some observations

Observation between, Purebred and cross bred litters I have had.
Disclaimer: This is done with my own rabbits, and not to be taken to seriously because rabbits all have different personalities and different lines mature at different rates. So it won't be the same outcome for everyone.

Purebred Argente Brun litter:
-I have very similar sized kits in the litters. No runts, all sturdy kits.
-Really great meat qualities. No boniness what so ever.
-Fast growing. 5lbs by 8 weeks. (It's funny seeing an 8 week old baby larger then my biggest Mini Rex)
-Silvering comes in patches.
-Very friendly rabbits.
-Does not eat that much compared to size.

Cross Litter (Argente Brun X Harlequin)
-All different sizes, runts, large guys, and some in between.
-Very Weedy, lots of bone. Not very sturdy rabbits.
-Some were fast growers, some not so fast. None of them reached 5lbs at 8 weeks.
-Silvering came in strange. Like scattered hairs through the coat.
-Definitely not consistent in anything but personalities. (Very sweet rabbits).
-They eat a TON, actually more then a ton, yet they aren't growing that fast at all.

Purebred Mini Rex Litter
-All similar sized kits.
-Matured fast.
-All similar personality wise.
-I was able to accurately guess their mature weight while still very young.
-Eat A lot.

Purebred Jersey Wooly Litter
-Similar sized kits
-Matured at the same rate
-Accurately able to guess mature weight when kits still.
-Does not eat that much
-Very Reserved

Jersey Wooly X Mini Rex litter (raised by a Mini Rex)
-Very rangy, unusual for Mini Rex and Jersey Woolies.
-Matured slower (Like a Jersey Wooly).
-Shy personality (Like a Jersey Wooly).
-Typed like a Mini Rex
-Really strange fur.
-Did not eat that much (Like A Jersey Wooly)
-Died when I hit some bad feed, even though his cage mate who ate like a pig (Mini Rex) Lived.

Purebred Netherland Dwarf
-Small, similar sized kits
-Very Energetic kits
-Slow to mature
-Eat quite a bit compared to their size.
-More independent rabbits, didn't necessarily like human contact.

Jersey Wooly X Netherland Dwarf
-Very skittish babies
-Different sizes
-Very Slow to mature
-Ate quite a bit for their size
-They all had Wooly heads (if you've ever seen one without wool)

What I've learned from this is: You can't breed two different breeds together and assume you'll only get the good traits from each breed. Genetics don't quite work the way and you can have a completely random outcome the next time around.