The classic collections I'm most excited about are the Capcom and Taito collections, however those are not PSP titles as of yet.
The Namco collection has a few highlights, the most obvious being GALAGA. Other notable inclusions include Rolling Thunder, Rally X, Bosconian and Pac-Man.
A few games have updated versions included with the classics. For example, with Rally X “Arrangement” you have fully 3D buildings but the game maintains the top-down perspective of the original.
This collection would be worth buying for Galaga alone, but my only concern is the price which is substantially higher than the typical price for classic games collections and for what is the weakest of all the classic collections. To put this in perspective, these game used to cost 20 cents per play in the arcade, so you literally need to play this product 415 times to get your money's worth. That's a scary proposition.
As the only classic collection for PSP and the only way of effectively playing these games on PSP, for retro fanatics like myself the price may be overlooked.