Sony may not be making Clies anymore but I still think they are great PDAs. In fact, I think the TH55 may still be one of the best palm OS PDA's available. I know many will chime in that the Palm OS is dead or over - but I still prefer it over what is available today (I have been using a T|X for about 18 months now).
Newer versions of NetFront are not available for palm OS. At first glance this does not make much sense since Access (the company that makes NetFront) recently purchased Palmsource. As far as most can tell, the reason is that palm inc is using the Access engine in its Blazer web browser and there could be some sort of written or unwritten understanding.
I have used the old NetFront, Blazer, Webpro 3.5 and Opera Mini on my T|X. Honestly I think Blazer is the best available despite its many flaws. There are other web browsers out there including a new tab based palm os browser.