You 'almost' can't go wrong, you can get the money out with interest at the end if the share price has gone down. There is some risk in taking the share options at the end of the scheme and holding them rather than selling, but I've found it to be minimal.
My wife works for the same company and we took a 6 figure sum out of the last one that matured, that was for £15k invested over 5 years each: £250 a month!
If the shares go down over the first year I always cancel and start a new one. I did this with the last release, that is now sitting at £24K for £15K invested
🙂