It’s not that great a deal. It’s basically 4 days for the price of 3 but the difference between 3 and 4 day tickets is only about US$25 anyway. You can do better by purchasing from reliable resellers like aRes Travel, ****************** or if they have stock, Last Minute Travel Club. For LMTC you have to call but their 5 day tickets are only about $3 more than the 4 day so even better value. For comparison, my 5 day parkhopper tickets were US$332 or A$485 each for adult tickets. That’s way cheaper than a 3 day ticket on the Disneyland website where they are US$355. 5 day tickets on the DL website are US$395.
Another option I have heard of but not tried is to ask your travel agent to check prices with a wholesaler called Beds Online rather than whatever wholesaler they are using. That’s where my vouchers ended up coming from through LMTC and I’ve heard they are generally a lot cheaper than other industry wholesalers.
All the best.