I'm going to go against the grain here...
Is $130 really that high? In the Albany, NY area, $120/month seems to be the norm for full-time dojos. Contracts are also the norm. The dojo I attended is a little less than half the norm and has no contracts, but that's not really why I joined.
Then there's the first 4 belts at 2 month intervals thing. If students are learning what they need to learn for those ranks, what's the difference if they're 2 month intervals or not?
How do they define "intermediate student?" Is it the step after beginner? Maybe an intermediate student is a student that's learned and shown proficiency in basic blocks, strikes, stances, etc. I'd say 8 months is long enough for that. I'm not saying students regularly show mastery of the basics in 8 months, but they should show proficiency in them in that time frame.
If we're focused on time frame, real question is how long to black belt. And how proficient are their black belt candidates. From what I've heard of Isshin Ryu, they don't learn kata until about 8 months or so into the syllabus. I'm pretty sure once a student reaches this point, the promotions are far longer in between and the material is far more complex. I think they focus on the very basics the first 8 months or so before really getting into what separates them from the others. I also believe black belt is the standard 4-6 years of consistent training time frame.
I don't personally know anyone in Isshin Ryu. I've conversed with practitioners online and have come across some of their stuff. Way back when, I competed against some local Isshin Ryu students. By all accounts it seems like a very good style of karate. I haven't seen much "sport karate" out of them; they're a traditional Okinawan style that may have a few students compete every now and then to break up the monotony of training. I'm quite sure their emphasis isn't kata for show nor point fighting.
I'm pretty sure
@Bill Mattocks is an Isshin Ryu student. He's probably going to have some better insight than what I've said.
Even if Isshin Ryu is a great system, that doesn't guarantee that every single dojo is great either.