I had a similar question regarding plain old Blu-Ray and the rep at OPPO told me that if all I wanted to do is view Blu-Ray and not any 4K content, then I should stick with my 103 and not bother with the 203 or 205 as there wouldn't be any improvement. If you have any further doubts. give them a call as they are quite honest about their gear.
If the rep told you there wouldn't be **any** difference then that may be a bit misleading.
http://watershade.net/wmcclain/UDP-203-faq.html#how-is-the-udp-203-different-from-the-bdp-103