I have to agree with others here. What was already a tremendously frustrating experience has now gone from bad to worse with the 30-second refresh rate. Previously, when one failed to find the item one was looking for (which was nearly always), one could close the market and reopen it to refresh immediately to see a new group of randomly selected items. Now one must wait 30 seconds between refreshes, further reducing one's already slim chances of finding the item one needs.
Really, the market experience would be improved tremendously simply by giving us filters to specify the items were looking for.
