Are there any differences b/w those 2 services. Can you suggest me which one has to use in which scenario ?
When present as a built-in service, I would always use that first - it is code assured by SAG after all.
PSutilities are not meant as production code but as a starting point for your own development (copying to your package and modifying for your specific needs).
You will find other id generation methods on https://github.com/permafrost/tundra#tundraidgenerate .
I prefer using the services in WmPublic and not the PSUtils.
I agree with Gerardo and Mahesh.
If available it is always recommended to rely on the WmPublic-Services.
Not all of these services are available in all current wM Versions.
This is an evolving story.
If there is no direct build-in service available, I usually use the PSUtiliies-Service if available before starting developing my own services.
As I checked some of these services lately for our migration from wM 7.1.3 to wM 9.5.1 I found out that the new
Build-In-Services in wM 9.5.1 are Follow-Ups of services which are part of the PSUtilities-Package.
Therefore we analysed our usages of PSUtilities-Services and replaced them by Built-In-Services if this could be done without to much effort. Some of these were suspended for the next migration as they need deeper analysis for replacing.