Win 10 is a good system, winxp is easy to get stuck, win7 is slow, win8 is medium, and win 10 starts smoothly and quickly, which feels like the best system I have ever used.
Back up important data before upgrading to prevent data loss when upgrading fails (the probability is very small).
Win 10 will provide free upgrade before July 29th. If you feel dissatisfied, you can return to the original system within one month.