The Mahalo U-30 is not great but for the price (under £18) how can you complain?! If I was to be critical I would say that the fret wire is too heavy - pressing down too hard sharpens the note slightly. It also has very little sustain - but that might be at least partly due to the strings. Once broken-in, it stays in tune very well. Some shops have them set up properly but some don't and mail-order ones probably won't. Here are a couple of minor changes I made to improve the poor intonation. I have also added another page about the repair I carried out on the broken bridge of another cheap ukulele.

(click images to enlarge)

1. Using a suitable needle file (or possibly a nail file), file the slots in the nut to lower the action at the nut end. High action here means you have to press the strings down further to contact the frets, causing the strings to stretch and the pitch to rise. On mine, the strings were virtually on top of the nut with only a small notch.

We don't want to file the slots too deep so do a little at a time - if you file too far the string may buzz or not sound at all. Lift the string out of the slot and, holding the file at the same angle as the head, give it a few gentle strokes; pop the string back into the slot and check the action all the way up the neck, ensuring there is sufficient clearance and the notes are clear with no buzzing. Repeat as necessary but don't be tempted to take it too far - better to err on the high side. The g and A strings are slightly more awkward than the C and E because of the tuning pegs. I did this with the original factory strings but, if you intend to replace the strings with a better set, it might be better to wait until you've changed them before filing the nut. The factory strings seem to be considerably heavier than others I have seen.

2. I noticed that the saddle was being pulled forward under the tension of the strings and was not quite upright, so I added a sliver of card (the red strip in the picture, left) to fix it - I was surprised by how much of an improvement this made. Get a tight fit with the thickest card you can get in - I used a business card.

Update: After a year of pretty much daily use, my strumming technique has worn the front edge of the neck to the point where the ends of the frets are increasingly exposed and are now catching my fingers. This is caused by a combination of a few things: my nails, where I strum, the nature of my playing, the neck material (plywood), and not helped by removing the paint. I have added a strip of insulating tape to save my fingers.

Please let me know if you find this useful.