Speedplay Zero (Stainless Steel)
Where bought and price
Wiggle - ~$250 AUD + $15 for Coffee Shop Covers
How it is used
Everything - commuting/training/weekends/races
Speedplay Pedals are designed to be 1) Lightweight 2) Low Stack Height 3) Double Sided for ease of entry.
The main difference between this product and the other speedplay products are that the lightaction pedal has apparently lighter action to help you get in and out easier and you can't lock down the float. With the Zero, you can limit the float from 15 degrees down to 0. The "X" Series are like the lightaction without the light action and with greater float (20 degrees).
The pedals are very light in comparison to other brands (i.e. Look and Shimano). Bear in mind though, that as the locking mechanism is in the cleat, not the pedal, the whole assembly should be taken into account.
Comparison (both pedals - full assembly)
Speedplay Zero Stainless - ~324 grams
Shimano Ultegra - ~359 grams
Look Keo - ~288 grams
2) Low Stack Height
I was previously using Look Delta's and I immediately felt the difference in stack height. This apparently provides better power transfer. I'm not so sure about that, the reality is that the size of the pedals you're pushing on are rather small, but if you're worried about that insignificant level of efficiency you probably also wear a tin-foil hat so I'm not going to indulge you with further discussion on that matter (we'd be talking about fractions of a watt). The truth is, the low stack height felt better. I can't explain it, but it's noticeable and a big improvement over the Delta's.
Speedplay Zero Stainless - 11.5mm
Shimano Ultegra - 13.7mm
Look Keo - 17.1mm
It's worth noting that ski-binding style pedals like the Look and Shimano, have "friction" float, whereas the Speedplays float completely freely until disengagement point. It might even make a difference performance wise as it releases any tension from muscles in the twisting plane. Either way I certainly like the feel. It's quite comfortable.
3) Double Sided
Yes, they're double sided. Technically you don't need to look down at all, you can fairly easily feel if you're not in the right spot, but looking is a habit you need to break. It IS a nice feature, but don't get any false expectations. The method of entry is... interesting. Especially when they're new, it takes significant force to clip in (thankfully it's not too hard to clip out though). This takes a while to get used to. Expect it to take a month or more depending on how often you ride.
If you want double sided pedals because you commute a lot, you really should go for something like a crank bros cleat or similar. This is partly because the mechanical action makes it stiff to clip in and partly due to how quickly they can get damaged.
+Light (well, kinda).
Noticeably comfortable and "nice" to use (Low Stack Height + Free Float)
Entry without looking
Can fit four-bolt shoes (it's actually lighter and has lower stack height for four bolt shoes due to not needing to include an adapter plate)
You can lock the float down to 0 degrees if you're a sprinter
-Can get damaged super easily. Cleats are not just $12 replaceable items.
Require considerable entry force
If you buy these cleats, get the coffee shop covers. I'm not kidding, I couldn't justify paying even $50 for these pedals without cleat covers. The bottom face of the cleat is some kind of alloy metal and it gets scuffed up really really easily. I carry the covers everywhere and will put them on EVERY time both feet come off the pedals and they still look awful. You have to be so careful with them it's not funny. If you can buy replacement bottom plates and screws it might not be so bad (I haven't investigated), otherwise, get the cleat covers, and consider putting some safety tape or something over the lower edge to protect it. I'm considering maybe a layer of hot glue.
Another note: These are not maintenance free. The pedals have a grease port for a reason. You need to take this into consideration. It's really no big deal at all, but you can't neglect it.
Buy it for your road bike. (If you don't mind looking after them)
Don't buy it for your commuter.
Value for money
(Although personally I'd save the ~$100 and pay the 10 gram weight penalty to get the chromoly ones looking back.
And I can't begin to tell you how laterally stiff, yet vertically compliant they are! It must be the beefy bottom bracket...