I use Sharp XV-Z12000U now. I watch only dvd and cable.

I am thinking about a scaler.

Which one should I buy, Edge is newer but more expensive than Crystalio VPS-2300.

I would get the Edge. First off the VPS2300 is a bit outdated. But more importantly, that company has pretty much disappeared from any sort of support, so it would be a big risk.

I had the VPS-2300 and it's not capable or handling true 1080.

It's half baked and got some severe design bugs when it comes to scale HD.

I sold it as i was so annoyed.

Look for a Lumagen Vision HDP instead, can handle everything excellent.

Exactly...

Thanks for your comment.
Now Edge is better than HDP or not. How about vision pro HDP, is it ok?

The Vision HDP is also a great unit. The Edge is a bit better in many ways, but the biggest issue with the HDP is that it is no longer available unless you find a used one.