Durability - my first pair has 13000 miles on it and it is still in superb functional shape. Platform size - for long rides, no other system has done so well in keeping my feet and ankles from fatiguing. Retention - aside from track pedals, I haven't found anything to have more positive retention. Cleat position - the main brass cleat's being in line between the pedal spindle and your ankle joint makes for good power transfer on the upstroke. These pedals are quite elegant in their design, much unlike the new IMPACTs. The IMPACT design is significantly lighter, compatible with more shoes, more adjustable (although the effectiveness of the adjustability is debatable), and of course easier to get now, but my biggest complaint about IMPACT is that they just don't hold up like their predecessors do.
Except for the polished aluminum body version of this pedal (Criterium Pro, the one reviewed here), paint comes right off of these pedal bodies with use. Brass cleats don't help the situation. They're heavy at 460g/pr and the cleats aren't light either. They're not made any more! It's hard to walk in the cleats, but why are people walking in the cleats?
I bought my first pair of TIME pedals used to put on my first road bike, after having tried LOOK and Shimano pedals and being dissatisfied with their degree of retention. TIME was exactly what I needed, and I have found it to be superior in many other ways since I began using it, and remained fond of the TIME design ever since. 5 overall since funcionality is worth the extra weight to me. 5 for value since the per-year investment ends up being so low with this product's durability.