In what way other than the camera? Nokia flagships like this, the N95, N8 and more in that generation had some excellent cameras. The N900 had a resistive touchscreen at the same time the iPhone 3GS and Nexus One were available. The OS was a blessing and a curse.
One nice thing about the N900's resistive touchscreen is that it was pressure-sensitive. This was great for drawing apps (notably MyPaint), and I haven't really seen a similar drawing experience on a phone apart from Apple's Force Touch.
True. Ability to use with gloves as well. Apple could probably make the Apple Pencil work with iPhones, but it probably wouldn’t be worth the hassle.