What a coincidence (somewhat)! I was just in Ochanomizu for the first time 2 Saturdays ago! While I have been to Japan a couple of times already, I usually just end up in Akabane or Shinjuku music stores to get gear if need be. I've heard of Ochanomizu before but never really needed to go there because the stores I frequented would usually have the stuff I need already. This time it was different, the stores I go to didn't have the particular items I wanted. They were out of stock so I ended up asking how to get to Ochanomizu and never regretted it.
For me, the nice thing about "Ocha" is the number of guitars they have in total. Think of the guitar showcase in Guitar Center Arlington times 20! No kidding...there were just too many stores in Ocha that have a huge inventory of guitars. Don't let the store size fool you coz the stores usually have 3 to 4 floors devoted to gear with about 2 floors at least for solidbodies. Just ask how to get to the other floors and they will gladly point the way. Also when in Ocha, don't forget to explore the side streets as well because the stores there, IMO, have better guitars and more quality guitar inventory.
This is me and my tummy at a Kurosawa store in one of the side streets; about to get sick with the more than PHP600k priced Private Stocks:
Pricewise, I actually find Ocha more expensive than my usual go to places in Japan. Simple case in point is the price of Korg Pitchclip tuners at Shimamura, Ikebe and all other Ocha stores. They cost PHP700 there while it was only between PHP400-440 in Shimamura Akabane and Ikebe near Shinjuku. Even prices at Amazon.co.jp was a lot cheaper (and guaranteed delivery within 2 days). Having said that, there are nice guitar bargains in Ocha including a very nice looking used Suhr C2 which had a price tag of only PHP90K. Buying used items in Japan, whether via stores or ads, is almost risk free since the Japs (even salespersons) are usually straightforward and will tell you everything they know about a particular used item, including unseen defects, minute scratches and other problems.
Overall, Japan carries more types and brands of gear than HK and Singapore but I still find Japan pricier than SG. Prices in the US will always win hands down but Japan is still a nice place to go gear hunting in coz one might just find a trasure somewhere.