1. First hand impression:

Music123.com is very similar to other sites with respect to the structure. It's easy to navigate on the site and they offer you many ways to find what you're looking for.
The design of the site is very basic, but still it appears professional and credible.

2. Usability:  

Music123 is, as before mentioned, very standard in its construction. They stick to the simple things and it works! They have what is needed and no more.

They have the standard search box where you can search for key words. It is good to use, if it is a specific product / model you're looking for.

At the top and in the left side you can find the head categories. . (Guitar, bass, drums, etc.).
When you click on a main category such as bass, you get back more opportunities to sort and find what you're looking for. Here are the category split into brand, price range, gear, accessories etc.

3. Selection:

Music123.com has a solid range of products. Like many other shops, they keep to the more popular brands but they have a verry solid supply of the  well-known brands.
The not so well-known brands are represented but the supply is not so large.
 
At Music123.com you can get cash for your used instruments. All you have to do is to send your instruments to them and they will either give you credit or cash.
How much they will pay, there is no garranti for, and it is porbably not much.
But still it is a good option if you`re desperate to buy new gear.  

4. customer service:

It took me a while to find information on their costomer service, until I gave up and pressed the help button. stupid me, here is all you need to know.
 
Music123.com gives you as other Internet stores many options to get help.
  
-- There is a toll free phone number you can call open 4AM-11PM 7 days a week.
-- there is a International phone you can call but it is not a toll free phone number!
-- There is a FAQ page where you can see answers to previously asked questions
-- And email.
-- You can ask a product expert a question, and receive a answer within 24 hours. 

5. The purchase:

Music123.com is verry sinneler to other internets stores when buying your products. And its esay.
 
Just find the product you want and click the "Add to cart" button. Now music123.com offers you different kinds of accessories. If you are not interested  you can keep on shopping, and you can at all time keep track on whats in your basket.
When you are done shopping you go to your cart and push the "Checkout" button. If you are a new customer you will have to fill out the form with your name and address, etc. and your credit card information.

6. Delivery:

It is very difficult to find generale information about shipping terms.The shipping terms are first given to you, when you are done shopping.
Like other internet shops music123.com dont have free shipping but if standard grand shipping is okay for you it is still cheap and fairly fast.
 
It is not possible for me to see if music123.com delivers to Europe.  

7. Store evaluation:

All in all, it must be said that music123.com is one of the better internet shops in the market.
They have a nice variety of products, and their site is very user-friendly.
Their payment policy is easy to find and very fair. In addition, it is easy to contact the store, if you have any problems ord questions.
However I must say, that the shipping policy is a bit messy. It is very difficult to find the right informations.
I must also mention again that Music123.com offers you cash for your used instruments. For a musician who always is in need of money this is a great offer.