I have ADSB and my initial comment is that relying on it in a circuit is potentially suicidal for two reasons.
1. You do NOT want your head down looking at a screen and trying to make sense of positions - you don’t have enough time. You are just asking to lose situational awareness. You need to be looking out because things happen fast. This is especially important if there is confusion about north up/track up, someone with a bad radio, poor english, verbal dihorea , wrong runway selection, etc. or marginal flying skills like me.
2. Unless you can ensure that everyone has an operating ADSB out capability, you cannot positively ensure your own separation. You can receive a false sense of security.
Where I currently value ADSB is:
(a) setting up my circuit entry where there are likely to be multiple players before I make my entry and first radio call. I might decide to do an orbit and wait for the RV rocket behind me to go first, or helimed or Vicpol or firebird.
(b) away from the circuit, ensuring separation with the many aircraft I would never normally even see.
It’s great to have it but be careful to confirm what you see on the screen.