Hello, what is Blender Alpha? Is it like the Beta version? Then what is Blender Candidate? Do these builds crash?
Alpha is before it turns into Beta. This means that Alpha is usually less stable than Beta.
Candidate is a Release Candidate. This is the stage after Beta.
Alpha → Beta → Release Candidate → Normal Blender
Do the builds crash? Sometimes.
Can you use them for production? Sometimes. But if you are unlucky they can be unstable and even destroy you files. So if you use it be sure to make a lot of backups.
Personally I would not recommend it besides for really small projects in case the benefit of a new feature is really large.