This is a common question and there is an easy if unsatisfying answer. If you really like it, it’s good. If it makes you happy, it’s good. Actually it doesn’t have to make you happy; if the emotional response you get is enjoyable/informative or just what you like, it’s good. This is unsatisfying because most people want their assessment corroborated by an ‘Expert’.
Experts exist. They have seen a great deal of art, studied it and know a great deal about the artist, the works provenance and the techniques used. To the artist technique has a very specific meaning. It is what he/she uses to get a feeling, colour, perspective, or other required attribute into the work. They might have studied and practiced a long time to master this technique. An expert can tell you a great deal about this but it shouldn’t have any effect on whether or not you like it. An expert might be able to tell you what the work would sell for but this is only worthwhile if you intend to sell it. So again; if you like it, it’s good.
In general if a work has been copied (including the signature) to sell for profit, then I don’t think it is good. The artist might be talented and just need money but they will likely have some of their own work languishing in a corner of their home. So if you really think the copy/forgery is well done it would likely be worth looking into the artist’s own work.