Pros: Small, accurate, neutral, preamped, wide and realistic soundstage, can get very loud
Cons: Average built quality, underrated, hard to buy, limited potentials, no height or depth in soundstage
I purchased these in the need of a studio monitor, where listening to the HD600 everyday for a few hours have made my head hurting and ears ringing quite often. The Japanese engineered Fostex company has again lived up to their name, with the Fostex PM0.3 (not just their headphones are good, ya know!). Incorporating a small and personal form factor, but not losing neutrality and sound quality (soundstage, lows-mids-highs, accuracy and details, etc) at the same time in spite of a 3-inch driver.
The small form factor means more room for acoustics or other equipment setups. Though the built quality and materials are not top notch (fake wood, plastic, PCB, rubber, nothing metallic or fancy) they are backed by a 1 year warranty (authorized retailers only). The overall construction is above average nonetheless (you get what you paid for). The built-in amps power them to sonically reproduce adequately even without a solid-state/tube preamp. The sonic properties of these speakers are similar to that of even larger and more expensive monitors (compared to Audioengine, Mackie, etc.), while the soundstage is not the best in the industry, they do feel realistic and plenty enough. Instrument imaging and staging is very, very good. They are great all-rounders and perfect for any genre. The best point of all however boils down to this: you can listen to them at quieter levels, yet still hear all the details and accurate reproduction of your audio files. Amazing!
Moving from the good things, these monitors do have a few bottlenecks however: the small build leads to more money for a higher and dampening stand and walls, for the tweeter to be at the same level of your ears; the left and right cannot be inverted easily and would require swapping the L and R line-out cable connection, which can be frustrating for some perfectionists; lastly, the volume knob is on the back, which could be hard to reach or adjust for those who need to do so often without multimedia controls or a preamp with volume knob ready at hand. Personally, I think the most unfortunate drawback is while the unit has a MSRP of around 8000 yen (roughly 100 USD), it is hard to find one in North America under even 150 dollars (for around 200 USD you can get the PM0.4 (one inch bigger) which in my opinion from audition is it's only slightly better in overall SQ).
All in all, I recommend these as one of many solutions to any amateur or even professional audio enthusiasts/composers/producers who are looking for a very intimate yet revealing set of small active speakers. There are not a lot of small sized speakers out there that are active and as neutral as these. They even have great value if you can find a good deal/price!