Before I start this review, I'd like to make something very clear. Thomann do a really good job, as do other online shops, offering a service that for people who live far away from specialist music shops is a lifeline, allowing us to pursue our hobby despite the fact that we don't live close to a large European or North American city. Without shops such as Thomann, we'd be slaves to the sharks on e-bay, or simply we wouldn't be able to get the best out of our instruments.
Thomann are pretty good, but they're not perfect. On the good side :
1) they can normally answer pretty much all your questions on the phone, they have specialists on most musical instrument categories who speak all the major European languages, so their customer care is pretty good.
2) they apparently have a "no quibbles" returns policy, a friend of mine got a guitar from them that when it arrived he wasn't 100% happy with, he returned it, and got his money back - I'm not sure about the postage, but he was happy enough with his experience, and continues to buy through them.
3) their prices are fairly competitive.
4) they have a funky review system to help you make your mind up.
Now the bad side :
1) there is (as with all online suppliers) no chance to try before you buy. I bought an "own brand" Thomann soprano sax through them, and it was utterly unplayable in its standard format - i.e. with the supplied mouthpiece and what they called a "reed" but which resembled a splinter of bamboo that wasn't even cut straight. As I needed the instrument and didn't have time to mess around returning it to then get another replacement one, I bought a Yamaha mpc from a local music shop, and some Vandoren reeds. Even then the instrument was only 70% playable, as the bottome keys didn't seal. I had to spend an extra €70 to have it set up by a technician at home before I travelled. Granted, I could have returned the instrument and got my money back, but I'd have been without an instrument.
I wonder how many young and enthusiastic musicians are put off by receiving an utterly unplayable first instrument, and then giving up when after a week's effort they can't get a sound out of it?
2) Their "ratings" system is weird - you can only post and read ratings in the language of your home location, so if for example you write a review in English to reach the widest audience possible, if your home location is Spain, they won't post the review. Also, they won't allow you to compare their items with other ones they don't sell. I have a Hiscox flight case for my alto, and I would have liked to buy a Hiscox for my Tenor before I travelled to Africa last year. I got an alternative flight case from Thomann, a Jakob Winter which was slightly more expensive than the Hiscox, but when I tried to review the Jakob Winter, my review was rejected because of the comparison to the competition. I think this is nonsense, it's just their way of limiting negative comments. The Jakob Winter just about does the job, but no way is it as good quality as the Hiscox case, and people should have access to that information before they buy.
3) They obviously don't test-play or set up their instruments before they send them, see point 1) above. I have just ordered a Rampone & Cazzani saxello from sax.co.uk and they assure me that all their instruments are test-played and set up by them before they are sent out to their customers. After reading Abadcliche's somewhat worrying review of an R&C tenor he set up
http://forum.saxontheweb.net/showthread.php?179373-Most-beautiful-saxophone-I-ve-ever-disliked I'd say that this was a minimum requirement.
4) You should definitely do some digging before buying online, I was about to get my R&C from them; after checking around the web they seemed like the best option. Sax.co.uk seemed to be more expensive, but then I got in touch with them, and we managed to come to a deal on the VAT as I'm ordering from outside Europe, and with the guarantee of them play-testing the instrument first to detect any possible construction faults such as what Abadcliche picked up on, they were both cheaper and safer than Thomann.
5) They have a standard minimum postage fee that varies according to where you live - for Spain it's €20 - which they waive if you spend over €300. I find that hard to justify if you're buying stuff like books or sheet music, or reeds, so I tend to do about two large purchases a year, sometimes getting together with my friends so our total comes to over €300 to save on postage.
In summary, if you know the piece you want to buy, i.e. you've play-tested one of your friends' horn/mpc/reeds etc, or heaven forbid you have play-tested it in a friendly local shop, and walked out pretending you're not impressed, just to go and get it cheaper online, then go ahead. But beware, there are other options around, and sometimes they're cheaper / more reliable. Oh, and don't even think about giving their products a bad write-up, or they won't publish your reviews!