Maybe I am alone here but I am happy with my endowment that I bought.
I bought a 25 year endowment 5 years before I got a mortgage. But that meant when I did get the mortgage, I only had the mortgage for 20 years as I was already 5 years into the endowment.
It was for £30k with a projected maturity of £44k. Matured in March this year for £31k. As I had paid in some £14k, and it paid off over half of the original mortgage (since extended) off, I am happy enough with that.