I hate to wade into this debate, but I guess I will.
The way I see it is that things just don't line up perfectly like people may wish. This happens all the time in other industries, GPUs being a good example. Often you'll have competing products from two different manufacturers, but they are not priced the same, nor do they perform the same, so you have one option that is say $199, and it is a bit slower than a competing product from the other manufacturer, but that product is priced at $219. The consumer is left to decide which is the better value for them.
With these cars we have a similar situation.
I see it like this.
Mustang GT [base model] -> Has no real straight up comparison
Mustang GT [premium model] -> Has no real straight up comparison
Mustang GT PP -> 1 SS [Camaro has better performance, similar content]
Mustang GT Premium PP -> 2SS [Camaro has better performance, similar content]
No real performance comparison <- 1SS 1LE.
The mustang and camaro products just don't really line up.
I do think it's interesting that one can argue that a Camaro 1LT 1LE would be about as fast and have similar content to a Mustang GT PP [non-premium].
It's also interesting that the only competition for an SS 1LE is not a normal Mustang, but is in fact a 'special' car, and the 1LE is about the same performance as that car, for about $10-12k less [assuming you don't get the dealer marking up the GT350].
The MSRPs of these cars are staggered almost perfectly so that you can basically pick your price point and level of performance [depending on what you can afford].
Code:
$33,820 - Mustang GT
$36,815 - Mustang GT PP
$37,820 - Mustang GT Premium
$37,900 - Camaro 1SS
$40,815 - Mustang GT Premium PP
$42,900 - Camaro 2SS
$44,900 - Camaro 1SS 1LE
The cars that seem like they 'compare' to me are the Mustang GT PP and Camaro 1SS, [about $1k difference there], and GT Premium PP and 2SS [about $2k difference]. In both cases the Camaro has more performance and costs a bit more.
There is no 'base model' Mustang that comes even remotely close to the 1SS 1LE. In searching for some sort of similar performance Motor Trend is looking at the Cayman GT4 and M4 GTS [from a performance standpoint, not from a brand caché or interior quality etc]. I think we can all agree that the 'base' GT350 is right around 'as fast' as the SS 1LE is under most circumstances, and that the GT350R will need either a ZL1 or a Z/28 to have a proper comparison.
You guys are arguing semantics. Why? There are only facts. Base Mustang not a very good performance car, but maybe desirable for people based on personal preferences and pricing reasons. Base Camaro tremendous performance. 1LE Camaro incredible performance/$$ ratio. GT350R very fast car with neat tech which no current gen Camaro approaches in performance.