After a lot of research...I have found that the best PDAs are...
New...

HP4700
Dell axim x50
Asus 730w

Old...

Asus 716
Asus 620bt or 620


What I found.
Hp4700 is a good performer in many benchmarks, has the biggest screen (4 in), a great VGA display...but it has the new touch pad controls and many folks find it difficult to manage. I hear it is almost impossible to play Age of Empires with the new controls. Battery life is about 4hrs. This is my first choice...but because of the controls I won't be buying it. I will wait for the technology to improve.

The Dell x50 has a great VGA an a 16mb video chip and also has a decent battery life...but when I went to Dell site to purchase it...the cheaper price rose sifgnificantly as I added a few things. I wish Dell would stop doing this. I became frustrated and changed my mind.
The Asus 730w is an upgrade to the A730...in that it includes wifi (the w). It's display is astonishing...but it's performance in benchmarks does not meet the HP4700. It has button controls (as opposed to the touchpad) which might make navigation and gaming more reasonable. The down...and a big one...the battery life is terrible. So bad that Asus ships this model with an extra battery. You can order a newer battery with longer life; separately.
The A716 has the longest battery life of any PDA...boasting up to 19hrs in some conditions or configurations. It is loaded with features and is fast. It is cheaper than some of the newer models. It has a great button layout...good for games. The downs...it's screen is not nearly as sharp as it's predecessor the asus 620 (a good gamer with a fast performance and bright screen...also reasonable price) & 620bt(bt for added bluetooth)...though it does slightly out-perform the 620 in fps by about 2-3 fps in different configurations. The Operating system is Windows moble 2003 first edition (the newer pdas have second edition...this is also true for asus 620 models). You can not use bluetooth and wifi together...so you would use infra-red keyboard for the net. And it doesn't do landscape(neither does A620 models). Anyway, this is one of the best, older, pdas out there in performance, features and battery life...not to mention price. I chose this one (A716) to be my first pda, while I wait for HP & Asus to come out with newer models that have close to everything I want. I didn't want to shell out a lot of money for a top pda that didn't yet have a combination of good display, controls, landscape, the ability to do bluetooth and wifi together and most of all a good battery life; combined all-in-one yet. I figure the A716 will suffice for a year or two. My other choice would have been the A620bt. Though, I was really hungering for the HP4700...the touchpad turned me off ...I like to game.
I forgot to mention card slots (sd and cf)...but most of these models can do both. Also I didn't mention memory. But, most of these models are configured good as pdas go.
This is a rough personal review as to how I came to a conclusion to pick my first PDA. If anyone has more to add...please do. Maybe my choice wasn't the best...I guess it was more frugal and in line with what I wanted to do with a pda and the length of time I could do it without having to recharge. I am only currently learning about pdas.
Add any comments about pdas and my choice...I would love to learn more. Also, I hope this info is helpful to some. I also, hope that this will help folks navigate in any research they do for pdas by narrowing down the search and allowing them to go and read about all the other features I have not discussed (such as movie looping, camera, phone abilities, etc.)
frew of stew