Hi Elliot,
Welcome to TFP and Happy New Year.
There are several high quality Saltwater Chlorine Genenerators (SWG's) out there of high quality. The 3 most prominent I think are
Hayward, Pentair and Autopilot.
All of them are very good quality but each of them are also different.
For example, the Hayward Salt Cell (T-15) is the largest there is for that unit and its advertised that it will treat a 40K gallon pool.
The Hayward has a display that tells you the water temp, the salt level, and several other things about the water and the system.
For longeviety sake, TFP recommends a salt cell 1.5x larger than your pool. It wont have to work as hard to produce the same amount of chlorine as a smaller one so it results in a longer life if maintained properly.
The Pentair has the controls of the System built into the cell itself. So replacing the Pentair cell is a lot more expensive than a Hayward one. Pentair has the IC60 model (for 60K gallons), which would be great for you. On the downside, there is no digital readout that gives you any info about anything, only a series of red and green idiot lights.
I dont have any personal experience with the Autopilot system, but the word on this forum is they are very good units. Hopefully someone else will chime in on this.
Recommend to read about how to operate a SWG in the TFP Pool School. Here is a link for you.
http://www.troublefreepool.com/content/127-salt-water-chlorine-generators-swg
There is no way for us to know what your pool guy is going to recommend for you or how much it will cost. Generally, pool people lean toward one brand or other, but rarely offer a lot of different brand options.
As a rule of thumb, your pool guy is going to mark up his price 30-50% above the prices you see online. He also is going to have labor involved and only he knows how much that will be, but expect the installation to be probably be in the 300$ - 500$ range.
Here are some links to the mentioned salt systems. Recommend to study up on each of them so you can be informed when discussing with your pool guy.
If you have any specific questions about any of these SWG's, please ask and Im sure you can get responses in short order.
http://www.poolsupplyunlimited.com/...lt-system-power-center-and-salt-cell/143825p1
http://www.poolsupplyunlimited.com/pentair-ic20kit-intellichlor-salt-chlorine-generator/136320p1
http://www.poolsupplyunlimited.com/autopilot-dig-220-pool-pilot-salt-cell-power-supply/56646p1