Here is a comparison I wrote for a random thread, and thought I'd share it with other newcomers to BlazBlue / Guilty Gear styled games!
key terms to learn!
: "attacking someone who is getting up from a grounded state"
: "converting random hits into big damage" (yes this is a VF term with a different meaning :c )
Street Fighter focuses on footsies and strong ground games. To become the best player at the game, you must master the range of characters, as one whiffed attack can be punished heavily. Also, ground strings are very simple and to the point, with limited mix-up potential after 1-2 hits. Combos generally only start from the ground, and are rewards for the opponent not blocking a cross-up correctly, or whiffing an attack at a terrible range. Counter-hits generally do not reward you in obvious ways. In some games, meter management is very critical also, as it allows you to have an advantage later in the round.
Guilty Gear series focuses on the same issues as above, but add the concepts of okizeme and abare. The goal is to knock the opponent down in any way, and set up your okizeme pressure. Imagine if you could use Ryu, and trip someone. Then, throw a fireball and cancel it, and jump at them. They have to guess 3 ways as to what you will do next. If they don't block that fireball, they get hit, and you get another knockdown and the process repeats. If you hit them with high, low, or throw... those are your okizeme options.
Guilty Gear also focuses on Abare, which is the concept of, say... Ryu hitting someone with a max range crouching forward. In most SF games, the most you'll get is a fireball / super. However, imagine you could cancel it the fireball (again) and go into a huge air combo. Converting that tiny hit into a much bigger combo is a huge deal. However, Guilty Gear lets you do many different ways. Sometimes though a perfect anti-air, you get a 15% combo. A perfect risky attack may lead to a counterhit, giving the attack ground bounce abilities, wall bounce abilities, wall stick, etc. Playing strong footsies with characters can lead to counterhits that lead to 50% damage.
Now, Blaz Blue adds additional concepts to traditional Guilty Gear game play. While Guilty Gear focused more on guaranteed okizeme situations, where the opponent has to deal with your attacks, Blaz Blue gives you 4 ways of getting off the ground. They have varying risks, but prevent the type of knockdown -> generic block attack -> mix-up game play that is prevalent in Guilty Gear. With a strong understanding of your risks, and the rewards, you can escape okizeme situations.
Another interesting concept is the one of "being helpless in a combo". Normally, when you play Guilty Gear. combos can last quite a while. There is never a reason to tech, because nobody practices techable combos that may do more damage, unless they suck. So, the best strategy is generally never tech. BlazBlue's ground system allows you to infinitely combo someone until they're forced to get up. Throws can also combo, and do not prorate; meaning they do full damage. However, to balance this, a combo'ed throw usually has a massive escape window; which is very very simple if you're awake.
So, simply, but allowing you to combo throws, you force the opponent to always be on their toes in the middle of combos.
That was a bit much, but hopefully it made sense and is useful for you to understand the difference between games.