stylus for Acer Iconia W700

Be aware of the fact that the degree to which you can use a stylus is limited by the fact that the W700 does not have an active digitizer.  That means that there is no pressure sensitivity and the accuracy is much lower than if you were using a Wacom tablet or digitizer with one of their pens.

I don't have a lot of experience with capacitive styluses, but the one that came with my W700P seems very nice: it's heavy and feels good in the hand, and it's accurate enough to select small text, tick small check boxes, etc.  You can buy it separately here (or, if you're in Australia, that's the stylus that's offered in the Australian Acer store, I believe).  If you watch the video on that site, however, that demonstration seems to be substantially beyond what I, at least, have been able to replicate with the stylus on my W700P.

I think it works quite well on the W700.  I haven't used it a lot, but it seems to be easily controllable and accurate.  It's kind of hard to describe in words without pictures, but I'll try.  The tip of the pen is a 7mm clear plastic disc that is mounted on a spring, so the angle is flexible.  If you hold the stylus at a normal writing angle, say, 20-30 degrees from vertical, when you go to touch the screen, it's the edge of the disc that hits first.  Because you can see through the disc, you can tell exactly where the center of the disk is going to land, and it doesn't actually register as a touch on the screen until you press down a little bit so that the spring bends a little and the center of the disk comes in contact with the screen.  I don't know exactly what you'd do with the stylus in Excel, but I think it would be great for tapping on individual cells, for instance.  I have used it for dragging and dropping email from my inbox into various folders in my email client (Thunderbird), which requires a good amount of fine control and accuracy because they're pretty small, and I haven't had any problems doing that.

As for scratching the screen, I don't think that will be a problem; the stylus comes with little clear adhesive discs that stick to the bottom of the disc on the pen to cushion it and isolate it from directly touching the screen.