I went the SPX route and got the Columb CT500 charger. Luckily for me the SPX electrician was very honest with me about the problems with the SPX service - opportunistic mark ups. That problem is especially bad in my are (MA) as there are no utility/state rebates for EVSE installation.
Anyway the trick is that you should have a sub panel or disconnect installed near where you want the EVSE by your favorite installer before you call SPX. In talking with the electrician he indicated that he and others have been bitching to SPX and that they have been losening up on some of the requirements. For example, early on the rules used to require that the electrician hire a helper, even if not needed, AND pay prevailing wages. Apparently they are also relaxing the need to take a cut of the non-EVSE electrical work as well - such as main panel replacements.
So in my case I had a sub panel put in the garage outside of SPX (using the same electrician) then the EVSE was installed later. My cost for the CT500 setup from the subpanel was $800.
Other thoughts - I love the CT500 reporting capabilities and the solid non-coiled cord, although thick, is very easy to use. In addition the CT500 can deliver 30A (7.2Kw). As the end price was about the same as buying the voltec and installing outside of SPX I went with the CT500.
Some day I hope to get an electric car that can use the extra power
One final thought on cost - With the "free" chargers there is additional work that must be done beyond the physical/electrical installation to configure and activate the device. Also, the program requires an electrical inspection. Sometimes when people say "my guy can do it for $100" I get the impression they are skipping this step...