the apples to apples comparison of Exec Plat in the United program is 1K. For GS, the comparison should be the Concierge Key with AA.
The benefits of GS includes all of 1K and more.
There is a GS thread that discusses a lot of that in detail, but here are some of the key features that are important to me that the 1K status does not offer.
1. Highest level irrops handling (agents at the airport actually actively watch your incoming and outbound flights to ensure that you make the connection and adjust and accommodate as necessary. There is a dedicated GS team to ensure that happens in most airports and will often times meet you at the gate.) The key benefit is that they try to get GS customers to their destinations.
2. Highest level of upgrade clearence- GS clears 120hrs for CPUs. And it clears into PN versus R and PN>R. On international flights, if there is no upgrade inventory, there is a protocol that is somewhat unclear that a few days before departure, they can convert revenue seats to upgrade seats for GS members.
3. The GS desk- probably the most skilled and best trained agents in the airline and an email channel that is one stop and handles all requests.
There are definitely other perks but these are the most important to me.