Martin Logan Vantage vs Infinity RS 1b

Does anyone have insight into how these new and old speakers stack up against each other. Driven by Threshold S-500 Series II amps. Hard to let go of my Infinity's, but looking for more definition if it is there. Opinions?
I love the RS-1bs.They are tuneable and very musical.Had you thought about changing a cable,to allow more definition/detail?
Don't give up on the Infinitys.
keep the classic with other components
I can't speak directly to your two choices, but I moved from Infinity to Martin Logan.

I had Infinity 4.5 RS and the external crossover using two hafler 500's to power them. I had that setup for years and years. I was in Seattle with time to kill and went into a store that had the Aerius setup. I had a fond recollection from the 70's of an Acoustat 2.2 demonstration playing Vivaldi so asked to hear them. I was immediately struck by the transparency and soundstage coming from the small size of the speaker. I was not thinking of replacing the 4.5's but that clean demo and Acoustat recollection pushed me over the edge and I bought a pair of ReQuests to replace the 4.5's.

The ReQuests were cleaner, better at micro-dynamics, and more involving at low power and "normal" volume. The Infinitys were better at high volume and bass impact, power, and control. Both compressed at higher volumes and had bass discontinity but the Infinitys were better at hiding this trait. End result, I kept the ML's and sent my brother the 4.5's for his birthday.

I now have Summits next the ReQuests in the music room and am hoping for more and better integrated bass impact and some more volume before compression. (Just bought the Summits and haven't hooked them up yet). I use tubes now for both pre and power and Logans are more "alive" in my opinion using tubes.

So, you have some excellent Infinity speakers and have your eye on an excellent replacement. It really is a tough call and if you listen to say, primarily Slayer or Zep at high volumes most of the time, I would be inclined to stay with Infinity. As I have aged and started getting into Jazz, acoustic, alt-country, punk folk, etc at lower volumes than say "Live at Leeds" tripping 10 amp fuses in Haflers I find the Logans exceptional at lower volumes with less complex music.

One factor also is I used to send my EMIM's to Infinity to get re-done and could order replacement EMIT's. Near the end of my ownership Infinity stopped supporting and repairing and replacing drivers. With Logans replacement parts should be available for quire some time.

You have a nice quandry. I really enjoyed my Infinity's but I still feel that the Logans are a definite step-up.

Good Luck and Have Fun.
why not borrow a pair of martin logan speakers and decide for yourself ?
Thank you all for your opinions.
Tpsonic: I am using some very nice silver cables and do not believe there is but an infitesimal amount of definition let to be had from the RS-1b's.
Steelhead: You have solved my dilemna! My existing Infinity setup uses a Bryston 10B as a crossover and not the Infinity recommended unit which is a VAST improvement. I equally play jazz and symphony as much as Led Zepillin and Garbage so both spectrums of loudness and definition which you eloquently stated are needed. With the age of the Infinity system I have to believe that sooner or later components will need to be replaced and the large footprint is a consideration as this upgrade is being made to accomodate a room built specifically for audio and video.
My decision has been to go with the Vantage speakers and keep the Infinity bass towers. Before testing I believe a crossover at about 150 to the Infinity bass towers from the Vantage should render considerably more bass impact without compression. From 400 down to 150 the Vantage can hold the easy bass with it's own amplifier, and then the Infinity bass towers should dessimate the sound waves between 150 to 20 being solely driven by a Threshold S-500 Series II amp. The clean Bryston crossover being active will give the chance to blend signal strength in the bass region. I also utilize a Velodyne HGS-15 for the subsonic portion for the all important theatre experience with a crossover point at 80. It looks good on paper and tomorrow we will hear this unique setup!
Let me know how the Summits stack up for you Steelhead. For me the Thresholds amps give exactly the right combo between the tube and solid state feel for music. Straight tubes are just a little too soft for me, but whoooo are they musical. Thanks again.