First off, what Gracie school is it? There are a few of them.
I train at a Humaita affiliate, which is a weird mixture of competition and self defence focused. But one of my main training partners outside of class is a 10th Planet guy. (it's like a strange buddy cop movie at times)
Honestly, no one here unless they are from where you are from is going to give you an accurate picture. If I were in your situation, I would go and do a trial at both schools and whatever coaching/teaching style you liked better, that would be the school I chose.
The reason being is that while certain Jiu Jitsu schools have specific games, you will probably end up gravitating towards certain techniques regardless of where you train. For example if you end up at the more traditional Gracie school, you will find people inverting and doing berimbolos, likewise at the 10th Planet school there will be people playing very traditional games too or the latest modern games, different from what you would associate with the standard 10th Planet game.
The main difference is the gi/nogi focus. Gracie schools tend to probably be closer to Judo (we do Harai Goshi against punches as part of our self defence curriculum for example) so a large part of your choice could be, do you want to compliment your Judo with similar techniques you can use in both (for the most part) or do you want to expand your grappling with techniques that you might not use in Judo (or Judo you wont use in BJJ).
Some general likes and dislikes I have from training with both mentalities. I really like 10th Planets warm ups, they basically drill a curriculum of set techniques. Which in my opinion is way better than running and is a great way to get better quicker. The other thing I like about the 10th Planet approach is the "fuck it" mentality. By that I mean reaping leg locks, neck cranks, spine locks etc are all good for the most part, where as Gracie schools tend to stick to IBJJF rules which when were just training i'm not a fan of. I like the stand up focus of the Gracie schools though (i'm sure your Judo will be leagues better though!) and I like doing a bit of self defence from time to time, doing techniques with strikes and learning headlock escapes etc is pretty valuable imo. I also don't think I could go to a purely nogi school. While I probably enjoy nogi a little bit more than gi these days, I still love the extra techniques and subtle differences you get training in a gi.
But like I said try and trial both places, a good fit with the instructor is the best quality imo, with price, schedule and location close behind. The difference between styles can vary greatly from school to school, especially in pure MMA schools where I have seen excellent grapplers and then people who probably wouldn't have a blue belt teaching the Jiu Jitsu. Unless you want to be an elite level competitor, the "style" associated with a certain gym will not impact your game to a huge extent imo.