Depends what you are using it for .............
We use our RIB for 99% fishing so a good sonar is important to me.
I use a 95SV and GT52 transom mount transducer. This is the recommended transducer for both the 75SV and the 95SV, but spendy at about £250. This is a good setup and I can easily see wrecks etc in 200ft of water.
My new boat has been ordered with the echomap plus 95SV (Wifi & touch screen) and again the main transducer will be a GT52. However, there will also be a second panoptix live scope transducer for forward looking and extreme detail of the water under the boat ...... the panoptix live scope transducers are £1500, which is a load of money to be hanging off the back of a boat