We have had so much rain here I have not been able to use it much. Have put about 5 hours on it. So far I really like it. There are two things that I do not like. The oil level is very hard to check with the FEL attached, and in bright sunlight the dash lights are very hard to see. The rear remotes are standard on the TYM, and I think the remotes are extra on the Kioti, and LS. The 554 has a Yanmar engine. The 503 had a Perkins. I think you will be happy with any of the tractors you are going to look at. Last time I talked to the dealer he had not heard anything from Perkins about the 503, but he did say that the repair shop had another 503 in the shop with the same problem.. I went by the dealer on Memorial Day, and he was closed, but did not see the 503 on the lot.