Yes, Cintiq is better.
Cintiq models have things that traditional tablet laptops don't, like pen tilt and rotation detection, better sensitivity, and not to mention the best LCDs on the market. They also aren't permanently connected to hardware that will be obsolete in a few years. So just like any peripheral, you can disconnect it and use it on a number of future PCs. But... they aren't portable. They are tablet displays. So don't expect to be going anywhere with them (except staying on your desk).
Laptop tablets on the other hand are very portable and come in a few different flavors. Primarily Touchscreen and Tablet.
The cheaper touchscreen models (like the tablet/convertible TX1000Z) simply have a touchscreen in front of the LCD. This means you have mouse-like capability. When you draw on the screen, you have two measures of sensitivity. On and off. No varying pressure. The TX1000Z is an aging system, but HP is still trying to get rid of them. You can get touchscreen equipped models for about $800 now.
Then there are true tablet models (like the tablet/convertible TX2000Z). Most tablets have a touchscreen AND an active digitizer. Meaning if you want, you can draw or tap on the screen with your finger (and get convenient mouse-like capability by touching the screen) AND you can use the supplied stylus and get active digitizer capability (pressure sensitivity and such).
I'm actually looking into purchasing a TX2000Z. It has Wacom active digitizer support and touchscreen support, and it's very cheap (compared to other models). The only draw back is it uses a power hungry and hot Turion X2- not the best processor for a 12" convertible tablet. Other more expensive tablets use Intel ULV processors which perform slightly worse than the AMD, but are much cooler and consume less power.
If you want to be mobile, definitely go with a tablet laptop. If you are an artist that needs all the high end features and gigantic display offered in the Cintiq line, then definitely get that.
I suggest you check out tabletpcreview.com and take a look at some on the market.
Good luck!
