SSanguan is correct re:lounge access. Reading the back of an ROP Silver card, it states 'Access to Thai's airport lounges is only available to First and Business class passengers and Gold status members.'

Silver status seemed to boost my upgrade-rate a bit, but at least for me, there are not enough program benefits to warrant extra effort to obtain silver. However, IMHO, ROP Gold may be a worthwhile consideration. Although the upgrade rate is quite high with gold, the primary advantage for me has been getting guaranteed reservations on fully-booked international TG flights (must make reservations at least 72 hours in advance). Over 50% of my trips to Taiwan, Hong Kong and Osaka involved at least one segment that previously I was forced to book with RQ instead of OK status. Now it's clear sailing with ROP Gold.