The problem for competitors, apart from trust and proven hardware is price.. can they compete with the price per Gh? Seriously doubt that unless someone new like KNC appear, which could happen.
KNC have been very clever at marketing and timing , I'd bet they have destroyed some companies like BFL completely. No tears there though eh?
I think the power issue isn't so much paying the bill, but the wiring involved. Most US houses these days, you might be able to squeeze out 2..MAYBE 4kw circuit. Beyond that you need subpanels, and ideally dedicated panels. Most folks won't do that unless they're already balls deep (like Phoenix for example).
Personally, let's say I could only support 2kw, I'd feel almost ill owning a miner which can only do 3TH because of the limitation, knowing that if I had more power it could go twice as fast. It's like paying 2x as much for a miner than you need to. I have a feeling the Neptune will be able to hit 5 or 6TH in the right conditions.
Yes, KNC has done well with their timing. I also point to their 'protect the network' claim as part of this. They're using it as an excuse for timing, but to save themselves from a bad reputation regarding time-to-market (such as what befell BFL).
Let me chime in on the power a bit. My father is an electrician (well, was, he's a few days shy of 75 years old now ) and I learned this stuff rather thoroughly growing up. If you live in a rental apartment, this is useless to you, but if you live in your own house or in a rented house with property, it probably isn't.
Firstly, there is nothing magical about this, and the equipment is cheap by comparison to what you are spending on a single miner. You can easily install almost everything by yourself with tools you can buy at walmart and equipment that you can get at Lowes or Home Depot, practically everywhere in the country. I am not familiar with the retailers for DIY stuff in the rest of the world, but I would imagine that it's not too hard in most developed countries.
If you have a shed, you can make it your mining shack. Add a 200 amp service panel, wire it for 240/120 which it's largely preconfigured for anyway. I recommend twelve guage wire, though 14 meets code for 15 amp circuits. 12 is only marginally more expensive, and is legit for 20 amp circuits. This, in a small shed, is a day's work if you've never done it before. There are a number of DIY books out there, the oldest still in publication being "wiring simplified", which I learned from at my Dad's orders when I was seven years old. It's technical enough, but not over the top. There are many others. You will want one 15 amp circuit for lights, coffee pot, etcetera, and probably want the rest to be 20 amp or 30 amp 240v RMS circuits. You're only talking five or six breakers here, unless you are trying to run 10 or more miners. In that case, go to 300 amp. Then, establish a separate account to that shed with your utility company. They will supply the meter, you just have to have the wiring in place and in most places have it inspected by a local official. If you can handle the fine work for an electronic device, you can wire a panel and the branch circuits in your sleep. This is monkey work after you've done it a few times. Apprentices do almost all of this sort of work on major projects, with the journeymen supervising and doing some of the more complex stuff, especially industrial. The last time I wired up a panel and ten branch circuits was about ten years back, helping a friend update his house. The only hard part was running wire inside existing walls. You won't have that problem doing it in a shed, just run 'em in the open and fasten the wires down real tight. It took me about ten hours doing it on a remodel. In the open, it would have been maybe three.
There are several advantages to this approach. One, you have dedicated power. No line spikes from the heater coming on, or the stove, etcetera. Two, your power bill for the mining rig is easily accountable as it is it's own bill. Three, any wiring problems will be EASILY traced, as the wiring is right in the open, and four, the cost of the equipment is cheap by comparison. Maybe a thousand dollars, if you don't watch for sales and discounts.