Rick, Where are you thinking of detecting. Why I ask if its in Vic I would suggest a 2300. If in WA the 2300 or 4500.
To me in Vic where detector operators have been going over the goldfields using Doug Stones Maps and John Tully's more detail maps ( since the late 80's) I think the 2300 is a better first detector.
I agree with the above comments the 4500 its a great detector it has been good to me ( I sold mine and early model last year for $2600) I just think the 2300 has the edge in Vic eg A group of us went to Vic a couple of months ago for 5 days or so most of us with 45's, 5K and 7K's found 3,4 or 5 pieces the guy using his wifes 2300 found 68, and 2 or 3 with his 7K.
Peter