Tesla Powerwall: not much cheaper and also a bit wimpier than existing batteries

Seems like the original article is way more positive than the click-baity title by The Register:

"So to get 1 kWh of usable storage in a lead acid battery you are looking at spending closer to $800. This makes the Tesla more like 2/3 the price per ‘usable kWh’ compared to good quality sealed lead acid batteries. Not bad. But wait, there’s more…

2) Battery Life The Tesla battery comes with a 10 year warranty and an optional 10 year extension. This is huge. Most lead acid batteries come with a 1 year warranty. Let’s assume the battery gods smile upon you and your lead-acid battery lasts as long as it’s specification (1,200 cycles). You have only got 3-4 years out of it until you need a new one.

If your Tesla battery is going to last 3 times longer, then its practical cost over 10 years is actually less than a quarter of a comparable lead acid battery. Now we’re talking!"