I'm very interested in redirection services ever since I noticed amazon.co.jp has Topre keyboards starting for as low as 100 euros

(Also Leopold's topre appears to be only 130 euros locally and shops may also offer products that simply don't exist in the west: rare keycaps, other tech sets, Japanese boards for exactly the same price, etc.)
I had heard of tenso.com sending from amazon.co.jp or other Asian shops.
What are your experiences in those services? Are they fast? Do they ship reliably? Are you getting customs fees? Though I guess it might largely depend on the country. e.g. here we have a 150 euros free customs limit, elsewhere it be might lower, higher, none or free.