If you set them up right you cant tell the difference.
The tablet resolution is how many lines across the tablet surface it has. The higher the res the less distance between the lines. This means tighter detail (in theory anyway). As far as 512 vs 1024 LPS. I cant really tell the difference. Its all up to the individuals technique.
Its just user preference. Its all opinion.
Wacom has been around for a while and they make good stuff. When other companies started making tablets (that were less expensive), they answered with the Graphire models.
If the prices were the same for a 9x12 Intuous, I may consider it then. But I will take the Aiptek over the Graphire anyday. The Intuous line is nice, but not $400 more nice.
Like I said I have both, I use both (they are each on a different computer here in the studio). If you use one and then switch to the other, it takes about 30 seconds to adjust.
I was a hardcore Wacom fan like everyone else. Why? Because thats what I spent my money on. When I needed another tablet I decided to try the Aiptek. I could always take it back. That was 3 years ago…
Wacom rocks. Aiptek also suits my needs and has never let me down. I did have driver issues with the Wacom. Sometimes it didnt start up, or it would draw the heaviest line all the time. A restart always fixed it.
Be happy with what you have.
Its the artist not the tools.