This is the sprue with the dwarven rifle/crossbowmen:
As you can see, there are 10 of these sprues, with 2 dwarves each, and 2 crossbows + 2 rifles. One body already has the bottom piece of the rifle in his hands, so you can glue on a rifle barrel or a crossbow top.
The other body has no arms, and needs the crossbow or gun with 2 arms attached. So yes, you can make 20 crossbow dwarves or 20 rifledwarves or any combination.
The Revenge set has no shieldbreakers, dwarves with 2 handed hammers, but it does have 2 handed hammers in the sprues, so with some creativity you can swap some arms around and still make 4 or 5 shieldbreakers.
Here's the difference in sprues:
RISING: (REVENGE)
20 Plastic Skeletons (SAME)
-Hand Weapons and Shield or Spears and Shield
-Champion, Musician and Standard Bearer
10 Plastic Revenants (SAME)
-Hand Weapons and Shield or Spears and Shield
-Champion, Musician and Standard Bearer
15 Plastic Zombies (SAME)
10 Plastic Ghouls (SAME)
1 Plastic Balefire Catapult (SAME)
-Skeletal Crew
20 Plastic Dwarf Ironclad (HAS 25: 4 sprues with 5 ironclads + 1 command sprue with 2 ironclads, 1 standard, 1 musician, 1 champion)
-Hand Weapons and Shield
-Champion, Musician and Standard Bearer
10 Plastic Dwarf Ironwatch (HAS 20)
-Crossbows or Rifles
10 Plastic Dwarf Shieldbreakers (NOT INCLUDED, does have 5 2-handed hammers)
-Two Handed Hammers
1 Plastic Dwarf Ironbelcher (SAME)
-Dwarf Crew
So basically, Revenge has 5 more figures than Rising does, plus you can still make 5 shieldbreakers with a little creativity.
I only bought that set because it was discounted, being the last few sets remaining with the new box coming out.
Conclusion: it matters little. Get whichever is cheapest. I have 0 regrets, I love the models. Check my gallery for painted examples.