pdaXrom (that is Cacko X11, right?) is slower than Qtopia? and OZ-Opie?
No. In my point of view, they are as fast.
Is using pdaXrom OR OZ-Opie instead of Sharp linux worthy?
Yes.
Or a tweaked Sharp rom is better?
Yes as well. Cacko is better then default Sharp ROM.
Handwriting apps present in each of those distro?
pdaXrom is in heavy development and doesn\'t have handwriting apps. It could use Familiar/GPE apps thought.
Each distro has its advantages:_ QTopia/Opie doesn\'t use a lot of memory, applications are small and documentation & many tools are available. But small applications are not powerful and Qtopia/Opie lacks X11+GTK+QT/x11 compatibility. With them, any file coming from a standard Linux distribution can be used out of the box (Debian ARM or netwinder.org distro for example).
_ pdaXrom uses X11 and you can add default applications from ARM Desktop distributions. But it isn\'t built like an Open Source distro (I mean like Debian) but like a monolithic rom. It lacks compatibility with other distro (Debian package dependencies for example). It lacks documentation. Most applications are heavy. There\'s a lot of thing to do as it is just born. And unfortunately they are doing the same mistake as Sharp: the distro is not enough open and the work with the Open Source community is difficult because of this (as Sharp rom, it will be replaced by something more open if it doesn\'t change). It\'s also difficult for then to use something else (like OE build system) because they could completely loose their user base. But whatever they do, will this change something? If users choose something more open like OE/Familiar, they won\'t survive.
_ OE can build anything: X11 rom or Qtopia/Opie rom. Shortly, we should see something like OE/Familiar for iPaq & Zaurus (& perhaps other). At present, it lacks man resource, its web site is a mess when searching for something (and they don\'t want to recognize it), it is not as stable as pdaXrom and not as active too. More then this, they need to come back into people heart like it was when OZ for 5500 was released. Even if Linus Torvald have chosen BitKeeper to maintain the Linux kernel repository, people have been discouraged that OE uses BitKeeper instead of cvs to manage their source. The acid reactions of the OE leader on IRC or on Sharp forum haven\'t sort this issue out (on the contrary). Now people like Mickey are improving a lot the communication between everyone (and few of us expect a lot from this).
What you should do is to try them all and find what you prefer. At present, the 3 best working distro in my point of view are: Sharp ROM, Cacko ROM and pdaXrom (in random order).