The Rogue 88 sounds better in triode than it does in ultralinear. Since the Rogue can be set very easily in either mode you should try both and see (hear) for yourself which you prefer.
I compared the Rogue 88 in triode against a 300b SET and found that they are more similar sounding than different. The 300b worked better with single driver speakers (Lowther, Fostex, etc.), while the Rogue had more punch with efficient multiple driver speakers. Also, if you run the Rogue without the cover you can disable the fan, which adds noise. E-mail Mark O'Brien at Rogue and he will tell you how.
I compared the Rogue 88 in triode against a 300b SET and found that they are more similar sounding than different. The 300b worked better with single driver speakers (Lowther, Fostex, etc.), while the Rogue had more punch with efficient multiple driver speakers. Also, if you run the Rogue without the cover you can disable the fan, which adds noise. E-mail Mark O'Brien at Rogue and he will tell you how.