I have been using Wise for the last few months, never tried Western Union although it maybe something I'll look into in the near future.
Every time I send money through wise to my Kbank, it usually takes a few days or even up to a week. With Krungsi however, it arrives within a matter of minutes. The only issue with Krungsi is that there is a limit of 50K baht per transfer, according to Wise website at least.