I must preface this by saying that Sony needs to be wary of over-hyping/marketing the PS4 Neo as something new/different. If they try to segment the market, I think they can hurt themselves. I believe the PS4 Neo shouldn't be sold long-term alongside the vanilla PS4, but instead be the new default model (like slims replacing fatties in gens 6 and 7 more or less).

Due to new lithography and process technology, the Neo shouldn't be any more expensive to produce in comparison to the vanilla PS4, and in fact, it would be more expensive by quite a lot to continue producing both models. Neo should just slot in as a direct replacement at the same price within a year AT MOST, and hopefully more like 6 months or less to clear residual PS4 vanilla stock. Keeping the fabs running for the old 28nm stuff, or creating a new die shrink and running seperate lines for vanilla PS4 APUs would be stupid, wasteful, and more expensive than just transitioning the entire production process to the new standard Neo model. A 'premium' vs. 'vanilla' dual-offering would just put a bad taste in the mouths of consumers, cheapening the brand appeal rather than enhancing it.

The frankly wise decision to not make Neo-exclusive games just seals the deal. Over-hyping the Neo would just fragment their 8th gen momentum, risk alienating the ~40M vanilla PS4 owners, and in general be a bad strategy. Better to focus on continual software rollout, VR support, and competitive pricing.

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Now, as long as Sony doesn't choose the wrong path in PS4, and I don't believe they will, I do predict that :

By end of gen the PS4's Neo revisions alone will outsell the entire X1 cumulative sales from launch to EOL.

Only if the original model is phased out. The NEO is really a stupid idea to begin with, many would rather just buy the cheaper base model.

So my vote goes to waffles.

I wonder if neo is going to sell a lot more than PSPGO.

so basically you are saying that the amount of PS4s sold after the Neo is launched will be more than all the XB1s sold before the XB1.5 is sold?

You know this is like asking if more 500GB PS4s will be sold than 1TB PS4s right?

So you think if the Neo is $350 and the base PS4 is $299 many would just prefer the cheaper one? if that were true wouldn't the XB1 be outselling the PS4?

I agree if they make the ludicrous mistake of trying to offer both models for more than a brief period. If Neo launches soon, I think PS4 vanilla will disappear from the market either during or just after this coming holiday season. Most estimates for PS4 LTD @ EOL at around 100m, so this should mean 45-55M Post-vanilla PS4s will be sold to the end of gen. This follows most estimates of X1 EOL LTD at somewhere around 50m.

So in the end I think it depends on their strategy. I just can't see them continuing with both PS4 models for long. Particularly if Sony wants to push their 4K BluRay stuff.

No. 

HMM...NO

Its very possible that Neo will eventually become the standard sku and the original PS4 will be phased out which has happened basically everytime a console/handheld has had a revision.

Not that we'd ever know its sales.