INTRODUCTION
I looked for a review of an MP3 player to see how well the recording function works. I could not find any. I am a sound engineer and I do live sound for many different kinds of events. Recording long events to CD requires an unacceptable break to change CDs. Does MP3 provide an opportunity to record long events? . . .
Try to not cut yourself getting your new T30 out of the package. If you didn't lose the battery cover at least twice the first week, then you haven't figured out how to get the package open yet.   ;o)

The T30 is very small -- about the size of your thumb. The display is very small and the font is probably about 6 points. That's about half the size of the smallest characters on a Timex digital watch. Where's my magnifier?

CONNECING TO A PC
Win-XP SP1 would not recognize T30 on the front panel connectors, but it was recognized at a rear panel connector. Go figure... Thanks to BestBuy for the tip.

Unlike some MP3's that require a special program, T30 simply becomes a device on your WinXP system. You can Drag and Drop (or copy) files and folders to or from the T30. You can also delete unwanted files. You can also use Win Music Player 10 to "synchronize".

LISTENING
Listening is a pleasure with preset and user EQ and enough volume to hurt. You can play just a directory or all music files.
Multiple play mode options. D = play the directory A = play all 1 = play the one selection Shuffle and repeat are available
If you need lots of unattended background music for your next event, an MP3 player will play music into your sound system for hours and hours at a time. What else is so small and convenient? Published battery life claims up to 24 hours. I doubt that's true.

The output level fades up when starting playback -- this is great for listening, but limits certain professional uses.

But the T30 also records!

RECORDING
I chose to try the T30 for recording more than listening. The line input function (up to 320 bit MP3) has plenty of quality to record, then edit on a computer, and then save a file of excellent quality. Many events last longer than the 74 or 80 minutes of a CD (concerts, weddings, funerals, lectures are good examples) . The T30 will record until the battery goes dead! A fully-charged name brand NiMH AAA battery recorded for almost 4 hours at the highest-quality line setting. That is plenty of time to get to a break in the action and change the battery. (Conventions and seminars can go on and on!)

The on-board Mic is very good.  It has no level adjustment and no AGC but is perfect for classroom recording. (You can use a computer audio program with dynamics processing to help with this.) Excellent for dictation and spoken notes. Concert level music is too loud and results in clipping. There are no record level indicators. This is a necessity if you're recording a band through a sound console! 

No track advance like a CD recorder, the recording must be stopped and restarted but that only takes about one second.

Timer  --  The T30 will start playing by itself at a preset time, but timed recording is not available.

Battery Life  --  The battery goes dead more quickly when recording, so carry spares. NiMH batteries last about 4 hours when recording.  Play mode life is much longer.

Size and Weight  --  The T30 is slightly smaller than a 'D' flashlight battery and less than 1/3 its weight, even with the battery installed.

Uses  --  Use it in the classroom, in meetings, etc. to take notes. Use it with your digital camera to comment on each picture as you take them. Record concerts, events, church services, etc. (when legal). Connect to a professional sound system to play background music or record an entire event.

Summary  --  The T30 is not a professional device. I would suggest looking at the Edirol R-09 or the Tascam DR-07 or the Zoom H2. These recorders write to removable compact flash "camera" cards and have all the bells and whistles for professional recording. However, these units cost $200.

Consumer devices can provide professional level results. I purchased a used consumer CD recorder a few years ago and it still makes perfect CDs. The T30 will also provide great results at a great price.

SOUND QUALITY INFORMATION
These are the details for the files the Iriver T30 records through line in (you can choose from 3 levels of quality -- high, medium, low)

At high level: MP3 320kbit 44100Hz Joint Stereo At medium level: MP3 256kbit 44100Hz Joint Stereo At low level: MP3 128kbit 44100Hz Joint Stereo * In joint stereo, some sound is encoded as mono.

LEVELS

Voice file  --  No adjustable levels; is over-recorded only on those parts that are quite loud! (So it mostly records right!) Church music is overrecorded. Classroom recording is good after dynamics processing.

Line-In  --  At Level 24, the music recording out of a sound board is good. Home stereo recording at level 28 is good..

BUGS AND ISSUES
If the battery dies while recording, the file may be corrupted.
Needs a recording VU meter.
Needs a voice recording level adjustment.
Can't get the alarm clock to wake up in the record mode.
Battery cover should be more secure.

Conclusion  --  In my experience, the unit has been TOTALLY RELIABLE with no hiccups ever and the sound quality is never an issue. Low priced and nothing else like it available.  Not bad . . . not bad  at all!  :o)