I don't think so. I just don't see the point of putting down an extra $300 for a Nexus S4. I mean, is the hardware really worth that much extra?
No, and if I may be frank I don't understand why people expect it to be.
The Nexus 4 is subsidized, and rather significantly at that, by Google. Google breaks even or loses money on the sale of each and every Nexus device, whether it be 4, 7, or 10. Because Google wants Nexus devices in the hands of developers and Android enthusiasts. Making money on unit sales is not their goal. Getting devices into hands is.
Samsung, on the other hand, is filling what they feel is a niche - a product that has top-shelf specs and gets more regular updates.
Unlike Google, Samsung is not in the business to get devices out to people at break-even. Samsung wants to make a profit. As such, they simply cannot compete in price with a company that is OK with not making any money.
The S4 is *worth* probably $100 more than the N4. Maybe a little more, maybe a little less, but somewhere in that ballpark. The other $200 is the profit Samsung wants to make off the device, third-party-sale markups, and the like.
Now the real question is, for the folks who skipped over the N4 because it lacked a feature you wanted, is $300 worth getting that feature? I'm talking about people who wanted things like LTE, a removable battery, an SD slot, a better camera, etc etc. Personally, if I were in the market for an unlocked smartphone, I'd look at a 13mpix shooter and say "the difference between that and an 8mpix means I might not have to buy a purpose-built dedicated camera for photography" or look at the removable battery and say "I could buy an extended battery and not be so dependent on carrying around a separate battery pack or be looking longingly at the nearest tree hoping it has a USB port" or look at the SD slot and say "I could carry around my entire music collection without an OTG cable dangling off my phone waiting to snap my delicate USB/charging port".
If it is, then the phone is worth $300 more... to you.
If it's not, then the phone is NOT worth $300 more... to you.
Others, using other criteria, may well reach other conclusions as to its relative value. That doesn't make your assessment of your own criteria wrong.