Avic-6000NEX vs 7000NEX vs 8000NEX

[MightyMouse13]

I know everybody hates threads like these, and the answer is probably going to lie somewhere in the "I dunno, it's your car" camp, but I just bought a high quality flamesuit, so it's cool.

I bought my car used with a Pioneer Avic-F90BT installed. Not a fan of the system, so I'm planning to remove it and replace it. I looked into the Kenwood DNN990 and 991HD, but after reading up, decided I couldn't trust the product and would go with Pioneer.

Where I'm hung up are two things:
1) Is the capacitative screen of the 8000NEX really worth it? I don't have many complaints about the touchscreen capabilities of the current system, but for ~$100 difference, I wouldn't mind paying the extra for easier use.

2) 6.25" vs 7". How much of a usability difference is there?

I've ruled out the 5000, because I feel like without the HDMI port, it's likely that the system becomes dated faster, and I don't plan on replacing this system any time soon.

The other thing I'm considering is leaving the current Navi in, and pre-ordering the Navdy, but I do have some questions about it actually fitting decently on our dash and not just being in the way. It looks like a fairly hefty mount.

Also, if anybody has any other suggestions for a high quality in-dash navi, I'm definitely interested to hear opinions and recommendations on those.