I had a 59 Clem H from the first run, and now have a 56 Suzie. In both cases, I'm pretty sure mine were the first frames pre-ordered from Riv. - I had followed the development closely and both spoke to me as being the perfect bike for what I wanted at the time, and I pulled the trigger the second they went live. Here are some random, rambling thoughts and impressions. Keep in mind as you read this that, although we'd ride the same size frame, we'd have entirely different experiences. I'm about 4" taller than you (6'-2"), but have a shorter PBH (87).
First things first: They are very different bikes! When I ordered the Susie, I thought it was going to mostly be a "perfected" version of the Clem, and that it would solve a couple of the minor but nagging complaints I had about the Clem (slightly too long of chainstays and too little standover clearance for trail/mountain use; too short of a top tube for a good fit; too flexy of a frame). The Susie did rectify all of those things, but I was otherwise completely wrong about one being a direct replacement for the other - there are very few similarites. I kick myself daily for getting rid of the Clem. Not not because I liked it "more" than the Susie, but because I could have found a place for both in the quiver had I known how different they are, and had I known that almost none of the parts were transferable from one to the other - which meant that I had to re-purchase a lot of pieces that I hadn't intended to.
In terms of ride/stability: The Clem feels like a true Rivendell, with a low center of gravity, stable and instantly comfortable. The steering is pretty quick - like a relaxed rivish road bike more than a mountain bike as I was expecting when I got it. As a result, it was quite (most) enjoyable on pavement and at speed. With the long wheelbase, it differed from a "regular" road bike in that I felt like every bit of effort translated to forward motion. Kind of like a speed skate versus a hockey skate. The Susie, on the other hand, has a very-noticably higher bottom bracket and, therefore, center of gravity. It also has a more relaxed steering geometry. So it feels like a lot of mountain bikes or off-road touring bikes, but without that distictive "rivendell" quality. Less effort for slow-speed cruising around. Even though the Susie is lighter gauge tubing (and lighter overall), it is less flexy than the Clem. On rough trails or standing out of the pedals, I'd got shimmy on the Clem, as I felt the whole frame flex torsionally. This is a guess, but I attribute part of the Susie's relative rigidity to the shaped chainstays that add better triangulation. The clem's are arrow-straight.
In terms of "wieldy-ness," the Clem was definitely a chore to bring along. I had to take the wheel off to fit it in the back of my pickup. I don't need to do that with the Susie. I don't live in an apartment or have to deal with stairs but, even if I did, I'd nonetheless gladly sacrifice a little convenience to own either bike. Both are big but, having gotten used to them, I can't imagine ever buying a short bike again - at least for trails and town and day-to-day use. I have a ton of bikes, but these are the ones I almost always grab. (This is when I kick myself the most for getting rid of the Clem - it felt more like an extension of me than the Susie does.) Unless your frame of reference is carbon fiber road race bikes, neither are heavy bikes by any stretch. Even with full racks and fenders, I never think about the weight like i do with some of my bikes.
In terms of suitability for electrifying: You're on you own... but Joe could probably help. I see the Susie as my heirloom forever bike, and I can't imagine bolting a motor to it or adding stresses that might damage it - but that's me. Personally, I'd get one of the cheap, heavy-duty Jones LWBs if I wanted to do this, or just get an off-the-shelf electric bike for less money.
Fit-wise, the Susie has too much stack height for me, with the bars I stubbornly want to use (bullmoose bosco) and, though longer, is STILL not long enough in the top tube. The Clem was marginal (almost too high) for stack height, but it worked. If you're flexible with cockpit choice, this can of course be fixed, but I basically find the Susie to be more restrictive. It even makes the steering a little too light for me, as I'm forced to be too upright and can't lean my weight forward enough. In your case, with a shorter torso and longer legs, I'd suspect that you'll find the top tube lengths adequate, but the susie's stack height will be shockingly tall.
I mentioned that my Clem H had a lot of flex - and mine even had the high top tube! I can't imagine the L being stiff enough, for the way I like to throw a bike around. And I understand the new ones are longer, wich should theoretically exacerbate the problem (remember the trouble they had getting the rosco bebe bike to work?). Yet I never hear anybody complain about this, so it's probably me guessing too hard. For probably the same, unexplainable-by-me reason, the Susie is adequately rigid. And, to politely disagree with Leah, I think it is one of the most attractive frame designs I've ever seen!!! The Clem L doesn't do it for me aesthetically. I do appreciate the low tube for crotch clearance when riding on trails, when I might suddenly get bumped out of the saddle or have to dab. But I mount a bike by leaning it toward me and swinging my leg over from behind the saddle, so the "step-through" concept means nothing to me.
On a related note, I mostly chose the Susie over the Gus because the early gus prototypes had kind of ugly proportiones with the 1 1/8" headtube. But the final ones, with a thicker downtube, actually ended up looking quite nice. If I did it again, I'd probably get the Gus for even MORE stiffness. Especially if I was going to electrify it.
On the clem, you can fit 2.4 or 2.5 tires WITH fenders. On the Susie, I have 2.8 tires, but there's absolutely zero room for fenders... even if there were some available in that size that didn't cost a fortune. As with all rivs, the crown/length of fork blades seems to be the limiting factor but, on the Susie, it seems exageratedly so. That said, I rarely ever wanted bigger tires on the Clem, and I think I do want smaller tires on the Susie.
FWIW