We have two methods to gauge the impact of a new Mac design on the public. The first is find out when our local Apple reseller is expecting stock and then talk to customers about their initial reactions.
The second is to set up the new Mac in the office and wait for our creative and techie colleagues to come and fawn over it. If the family man in the shop takes a shine to it, you know it will be a hit with the home market.
If the second group likes it too then you know professional types will be satisfied. After mingling with the crowds, the new iMac seems to have struck a good balance with both groups.
The 17-inch iMac has been scrapped (few are mourning the loss because you can buy the cheapest of the new 20-inch iMacs for the same price as the 17-inch 2.0GHz iMac, at £799). With the 2.4GHz iMac, you have the choice of a 20-inch or 24-inch screen size.
Of the two, we prefer the 20-inch model. Bigger isn't always better and the 24-inch model just seems overindulgent for everything other than watching films. A graphic artist would probably beg to differ, though.
Performance has improved, but it's the new exterior that's the main talking point. Apple has plumped for a sleek aluminium front and sides, glass for the display cover and black plastic for the reverse cover. The materials have a higher recycling potential and Apple is promoting the iMac as a green computer.
We applaud that sentiment, while secretly harbouring the notion that Apple is just borrowing design elements from its hot-selling laptop range and trying to sprinkle some sales dust onto its mid-range desktop.
The basic form is the same; a computer in a screen that perches on one curved leg. It's slightly thinner at the top and bottom but bulges slightly more in the middle around the back. A black surround borders the display, and the grey Apple logo is now black.
There wasn't much love for the old white plastic of the iMac among the professionals, and the new aluminium and glass design struck them as more business-like.
The family man was less bothered by the looks and found the iMac attractive for more practical reasons, such as the glass screen being easier to clean and more robust. More than anything, it was the inclusion of iLife '08 that appealed most. With it the family can make websites, movies and music with the latest Mac tools.
The one occasional complaint was the reflectiveness of the new glossy screen. Because it's made of glass, it can act like a mirror when the display is dark or a uniform colour. Unlike the MacBook Pro, which you can buy with either a matte or glossy option, all iMacs only come with glossy displays, which has irked some.
Our view is that the displays do take some getting used to and a matte option would have been nice. Fortunately the screen is very bright indeed, which goes a long way to combating the reflection.
We did find that some colours wash out on the iMac if you look at it from outside the direct viewing angle. We used LCDtest to drop the screen to solid colours and then swivelled the display to get different angles on the reds and blues and so on.
Colour distortion happens: this won't affect how any prints or designs output, and it doesn't occur when you sit directly in front of the screen, but if you frequently show off a design to colleagues crowded around your desktop then it may be a problem. Changing the default colour settings in System Preferences from iMac to Wide Gamut RGB helped reduce this problem, though.
We used Xbench 1.4 and Geekbench 2 to run general system benchmarking tests, and added in our own speed tests, such as copying a 1GB folder, iTunes encoding and startup and shutdown times. We then used Cinebench R10 and LCDtest to look closely at the graphics card and screen quality.
Some benchmarking tests are RAM-dependent, so if you opt for more RAM than us the results will change. The iMac can take 4GB of RAM and comes with 1GB as standard.
Overall we recorded an average 18% increase in general performance for the aluminium 20-inch 2.4GHz iMac with 1GB of RAM compared with a white 24-inch 2.16GHz iMac with 2GB.
In Xbench it scored 40% higher than a 15-inch 2.2GHz MacBook Pro with 2GB RAM, and was virtually neck and neck with a 2 x 2.66GHz Mac Pro 1GB in all but the raw computation tasks. That struck us as pretty special.
The Mac Pro only showed its bigger muscles under very heavy workloads that could flex the extra cores and really work the stronger graphics card. Some of the raw computation improvement was down to Intel's brand new Santa Rosa platform and the faster processor.
The Santa Rosa platform was only launched in May by Intel and has fatter pipes feeding data to the cores and better power handling than the older board. This produces more agile action from the iMac's innards.
The graphics card is faster than before and has 256MB of dedicated memory on this model iMac (cheaper 128MB option available), which makes the iMac better at handling games and movies.
Gamers take note; this card brings DirectX 10 support to the iMac, bringing cutting-edge, emerging technology to those who want to play Windows-only games on a Mac. Games, movies and graphics tools such as iMovie and Photoshop all fly along on the new iMac.
There was nothing really to separate the 20-inch and 24-inch 2.4GHz machines in the benchmarks, except during the graphic test, when the 24-inch produced slightly faster frames per second rate.
As an entertainment centre, the iMac is the Mac of choice: an all-in one design with everything you need. You get the remote, iSight webcam, the large screen, some great internal speakers, Front Row, iLife '08 and very little in the way of desktop clutter.
With the explosion of movie downloads, YouTube, digital TV dongles and the digital changes happening at the BBC, you could very easily double up the iMac as the family TV.
If you're thinking of upgrading to the new iMac there are two pieces of advice we can offer. Firstly, spend some time in an Apple Store looking at the new screen to see if it really bothers you.
And secondly, it may be worth holding off on buying the iMac until Leopard is launched, something we expect to happen towards the end of October. If you want to buy an iMac now and upgrade later you can, but waiting a month will save you around £100.