For comparison, the EPA rating for my 2008 Tesla Roadster to 26 kWh/100 mile city and 29 highway with a range of 244 miles.
I find that if I drive at a steady 55 mph on level freeway, I get energy use consistent with the 244-mile range. My best test of this was in March 2010, when I drove 182 miles at 55 mph and had 60 miles of range showing at the end of the drive. If I drive 70 mph, it's more like 175 miles.
Like the Leaf, the Roadster has two charge modes. Range mode gives you the full usable capacity of the battery pack and the full range. Standard mode gives you access to the middle 80% of the battery pack and about 195 miles at 55 mph.
After about 18 months and 14,000 miles, the range mode capacity has dropped to 234 and standard mode to 183, for a loss of about 5% of the range. Tesla has muddied the waters here by changing the way the firmware calculates the capacity of the battery, in a way that dropped the estimated range shown on the screen, so it's possible the loss in range is not as large as the reported numbers indicate.
In terms of power, I very slightly bested my quarter-mile time from last year, 12.978 seconds July 2010 vs. 12.982 seconds July 2009. I believe I've improved my launch technique, so it's possible the battery pack has lost a little bit of power, but is seems smaller than the loss in energy capacity.
In terms of day-to-day driving in standard mode, if I'm driving under 150 miles I don't even have to think about charge. I can drive however I like without regard to efficiency. For drives this short, the Roadster is completely care-free. Driving 180 miles, even in range mode, requires paying attention to your speed and often going below the posted speed limit on freeways. When driving to maximize range, I've changed my driving to take state highways with speed limits of 60 mph or less instead of 70 mph freeways, and optimize routes for distance. I like driving this way, the routes generally have more varied scenery and less traffic.
I'm assuming the EV range test hasn't changed from when the Roadster was tested in late 2008. From that, I have to assume that it will take some careful driving to get 73 on the freeway. In the 80% mode, it will take careful driving to get 58 miles of range, and 45 miles will be the range you can get in the 80% mode without needing to think about charging.
The most unhappy Roadster owner I know drives 200 miles per day on a regular basis. The only EV1 owner I've ever heard complain about the experience had one of the early lead-acid models with a 75-mile range and drove a 74-mile commute. I think a Leaf driver trying to get over 60 miles without charging on a typical day will be unhappy and anyone trying to get 73 miles regularly will become a vocal EV detractor. If you have Level 2 charging at home and can also charge at work, you can probably push up to 80 (120V charging) or 120 (Level 2 charging) miles.
If you're not sure these range numbers will easily meet your driving needs, I strongly urge you not to be one of the first Leaf owners. Wait until we have lots of real people reporting their actual driving experience so you can determine if the car really meets your needs.
My wife and I are pretty early in the list by order date, so I expect will get ours early in the process. We'll test the car and report what we find to the community.