The most helpful thing I think I can do here is to compare to the Zoom Streak LT3, which many of the people who are looking at this shoe will have worn.
Weight: GoMeb Speed 5 is under a half ounce heavier. Unnoticeable, but the difference is there.
Looks: The LT3 is one of the best looking shoes out there, and the GoMeb Speed 5 is pretty plain-Jane.
Value: Both shoes can be found for less than $90 retail and on clearance for less than $55.
Fit: GMS5 has a more accommodating upper, with overlays around the laces that really allow you to cinch down the fit. This comes with the cost of material scrunching under the laces. Both shoes have roomy toe boxes - for racing flats - and snug midfoots. I always felt like the ZSLT3 was a half size too snug, even for a racer.
Advantage: Push, depending on your preferences, but ZSLT3 is cleaner looking while GMS5 is more comfortable
Midsole: This is where the GMS5 shines. The Flight Gen material available in the Speed 5 and Ride 7 is LEGIT. In the Speed 5, you get WAY more comfortable cushion and a MUCH springier ride than the ZSLT3. Both midsoles are listed at identical 22-18, but the feel is night and day. The ZSLT3 is firm to the point of being harsh (but shines on the track, is that is your arena), whereas the GMS5 is incredibly comfortable, with more protection and energy return. My legs and feet feel better after a 10k in the GMS5s than they do after a 5k in the ZSLT3s. I wouldn't use the ZSLT3s in anything over a 5k, whereas the GMS5s could easily be used up to a Half, and efficient runners will be able to use them in a Full without issue.
Advantage: GoMeb Speed 5
Final Verdict: If I can only buy one, I am buying the GoMeb Speed 5. It is much more versatile over a variety of distances, and I believe the energy return of the Flight Gen midsole more than makes up for the slightly increased weight.