Fate/extra is okay. I'll start with the positives. The music is solid the graphics( for it's time ) is surprisingly good too. The character designs for the servants look good. That's all I can really say. Now for the downsides and mixed feelings.
The gameplay is easily one of the most frustrating and annoying things I have ever played. The rock papper scissor formula is terrible on your first playthrough and the game is very grindy. If you beat a route, the other routes becomes significantly easier, but the plot stays relatively the same, which is very disappointing to see, especially if you have played Fate/Stay Night which had a significantly different storyline depending on which route you'd picked.
The story is very lackluster. The themes are good, but could've been executed better. The plot is interesting, but the exposition dump at the end is so bad.The characters are relatively likeable, but they should've been explored more. I like all the playable servants except Caster. She is way too clingy and needlessly aggressive to almost everyone who isn't the bland main character, she's can be pretty funny though. Talking about the main "character" he or she is sooo disappointing. They don't have an interesting personality like Kiristugu, nor are they complex like Shirou. They are literally just walking stand in character for the player.
Overall, the game is a slog to get through, but it looks good. I would just watch someone else play through it to be honest, but go ahead and give it a try to see if you like it. It would've been better if was purely a vn.