I forgot about 5LP... so it's four product lines...
If as you say PSOC 3 has similar performance as 5LP with similar analog capabiliites, and PSOC4 is better, it seems to me that you're implying Cypress is phasing out PSOC3?
The PSoC 5LP family announced in December of 2012, did launch with improved pricing over previous generation PSoC 5 products. PSoC 3 has an 8-bit core (8051 based), but it is closer in system performance to a PSoC 5LP product with the same analog and digital performance in many cases. The PSoC 4 architecture delivers better core performance as expected from a Cortex-M0 over an 8051 and the chip architecture is significantly different from previous product generations. The first members of the PSoC 4 family will be well suited to reducing system cost through programmable hardware integration, while maintaining the ease-of-use that is expected for 8/16 bit applications.
So Cypress had old 8-bit PSOC3 and new 32-bit ARM PSOC5. Seems confusing that they created PSOC4 for low-end ARM. What is the fundamental difference between 5 and 4? I suspect it's a marketing 'wolf whistle' saying 'the prices are lower'.
The PSoC 4 architecture provides the MCU + PLD + Analog Fabric at a fraction of historical pricing. The product family was designed from day one to take on the 8/16 bit replacement market and to bridge to 32 bit ARM. The integration allows you to do some really impressive solutions like FOC based motor control, but at a much more reasonable price point. I think you will find our first PSoC 4 products can easily handle this market and be quite price competitive... More to come very soon. Thanks for your interest and question.