The short answer is that all couriers have issues.
It's hard to get an idea of which courier is good because everyone has had a bad experience with at least one courier. Despite that courier being very good and better than the average, that customer will automatically hate that company forever.
At my company we used DPD up until recently. We send out parcels which are all worth at least about £1000 and we've had quite a few of them go missing, get damaged, left outside customer's houses (which then usually go missing). Generally they are OK but the number of faults we had with them has risen over the past year.
We recently switched to APC Overnight. Whilst not totally fault free, they are a huge improvement. They actively contact us when there is a problem, which is new to me for any courier service. With DPD we would only discover a problem when the customer complains.
The best thing you can do if you regularly send out parcels is to get a goods in transit insurance policy. We have one with Aviva which costs £250 per year, and covers up to £5000 per parcel. They pay out very quickly and we've had about £4k in claims with them in the last year. Despite that, our premium has actually dropped from £320 last year to £250 this year!
When you look at the cost of insurance provided by the courier it usually doubles the price, at least, of the delivery. Having the separate transit policy is well worth it.
To actually answer your question however, the better companies I have dealt with are: APC, DPD, Parcel Force, UPS and DHL. The others are quite terrible and are priced accordingly.