I'd give this an 8/10, looking back on it. Overall, good gameplay, but almost no plot and some frustrating mechanics.
Compared to SFH2, the weapons system is much, much better. Upgrades were something we always needed, the blueprint/prototype system is great, and the classes with different (but overlapping) weapon slots is better than separate inventories.
I also like the ability to pick your team. Unique, earnable heroes are also great, although I think they should be unlocked throughout the game instead of having to beat a lvl 50 challenge for a hero that doesn't even start with any levels.
The different attachment slots are definitely an upgrade.
On the other hand, there were a few issues. I don't get the purpose of having days or getting tired, and the lag is just bad enough to be noticeable.
The players seem bigger. Moving doesn't affect aim much, so max range usually matters more
And it's just personal preference, but I preferred the old art style