Shimano PD-M647 Pedals

In the world of products being updated every couple years, especially in the biking world, the M647/ DX hasn't been touched in a long time since it was designed so well to start.

I've used these DHing, 4x/DS, and as my general trail bike pedal for years.

Positives

• Ultra Durable Design:In both the main clipless assembly and the composite platform they are both built to be incredibly durable. 
• The Platform: The plastic in the cage is super burly and slippery (more on that later), much more so than the cheaper Shimano M424. These has seen tons of abuse and are still going strong.
• The SPD Assembly: To say that the SPD design is proven is an understatement. There are a lot of little differences between the SPD designs, and even though these are not the lightest they have all high end features that you find on the XT and XTR pedals. The body is the more recent SPD design that is lighter and sheds mud better than the old design that is on the M424 and other cheaper SPD pedals. The bearing preload cone is metal unlike the plastic on the lower end SPD pedals (M520, M424, etc). I don't ever ride in the god awful east coast style mud pits so I've never had mud packing issues that seem to make eggbeaters more popular on the east coast. 
• The composite platform: In all my experiences the plastic on the M647 platform does a much better job than aluminum or magnesium at not catching up on rocks when you smash your pedals into them. The plastic that is used on this feels close to a HDPE material (cutting board material) or Nylon. Even though I'm not sure if it's different material than the M424 it certainly feels higher quality and possibly even a different plastic. 
• Rebuildable: Now I have to confess I do have a bit of a love hate relationship with cup and cone style bearings that Shimano uses across their range of products. But the HUGE upside on pedals is that you can always rebuild them and it's WAY easier to find 5/32" bearings that some of the really odd and niche sized sealed bearings that many pedals use. Also another upside is the ubiquity of the SPD system. Shimano has designed many of their pedals with the same parts across multiple products so that makes finding replacements or spares super easy even from 3rd party ebay or direct from China vendors. So even though sealed bearings do offer a more trouble free experience for the beginning and middle of life, in the long run cup and cone win out for clipless use.

Cons

• Weight: Yup these are definitely not winning any weight wennie awards but that's what you get for them being bomb proof and fixable. 
• Loosening of the platform: Because the platform isn't truly weight bearing and rides on bushings/ the axle it can seem like the pedal gets loose when it's just the platform. This is really just an aesthetic issue and doesn't affect the pedal's performance. 
• Less "secure" unclipped feeling over SPD with metal platform with pins: I hesitate to even include this but I know some people like almost feeling like they have a full platform pedal under if they fail to clip back in right away.