What's the diff between Match Across Virtual Servers and Match Across Pools?

The behaviour is quite different:

Match across services ensures that a client that has a connection via one port to a pool member will connect to that same pool member with a new connection on a different port.

client --> https virtual --> pool member 1

client --> http virtual --> pool member 1 match across services

Match across pools is used on a virtual that may direct content to multiple pools based on a policy/irule. The persistence record matches on the client ip address and sends to the pool and member regardless of the irule:

client --> http virtual "/url1" --> pool_1

client --> http virtual "/url2" --> pool_2

.........

client1 --> http virtual "/url1" --> pool_1 node 1

client2 --> http virtual "/url2" --> pool_2 node 1

client1 --> http virtual "/url2" --> pool_1 node 1 match across pools

client2 --> http virtual "/url1" --> pool_2 node 1 match across pools

I hope this is clear.