Had mine for 2 years now. Had 34000 miles on the clock when I bought it and now has 60,750 miles.
In the last 2 years its had:
2 coil packs,
new exhaust from the cat back,
brakes and discs all round,
most leaks sorted (still finding little ones)
new steering column shroud
rear washer jet and piping sorted
You will find that the above are common across the Leon range (some are general wear and tear). Not just the 1.4 in general.
Overall I'm happy with mine. I didn't buy it for massive performance. Mainly for econamy and low insurance.
If you do go for one. I'd suggest you go for a late 2003 onwards model as they came with air conditioning as standard. Pre 2003 models didn't come with air con.