K or long boi?

For my first mp5 clone purchase, I’m trying to decide which I want and looking for some opinions from folks who either have both or bought one and wish they’d bought the other.

My list of trade offs between one or the other so far are:
- sight radius/accuracy
- weight/compactness
- hand guard/rail space

Is there anything else?

I’m not sure if this is true but I have read some claims that long bois of certain manufacturers may feed all types of ammo more reliably than Ks.

Thanks in advance!