The concept is interesting... it's not better at finding primes than RIC or XPM because it doesn't look for primes, it looks for prime gaps which are relatively large ranges of numbers without any prime number inside. Kind of complementary to what we do. Their primes are at the start and at the end of the gaps.
This part of their "paper" is not accurate:
In Riecoin, it is even worse. Riecoin searches for prime tuples of length 6. Pools do accept tuples with less primes, but a 6-tuple only can occur in certain places. (Look at this post for a detailed explanation.) 4-tuples, by comparison, are more frequent. There are places, where a 4-tuple can occur, but no 6-tuple, which Riecoin truly needs. So pools have to check every submitted share whether the miner really searches for 6-tuples or not. Those facts are what make it so hard to create a Prime- or Riecoin pool.
This was true for the first version of pools and miners, but we've been using the "first + any 3" rule for pool shares for a long time now. This doesn't have this problem as looking for 4-tuples in places were 4-tuples can occur but 6-tuples cannot (to use their language) is actually slower than actually looking for 6-tuples (because we not look for strict 4-tuplets but ask for "first + any 3" of the numbers to be prime, if you strictly look for 4-tuples you lose a lot of combinations).
Also, they don't provide an analysis of the complexity of mining vs the complexity of verification.
The complexity of the verification of a proof of work in RIC is O(log(p)^3) while that of GAP looks like O(log(p)^5), meaning their verification is slower. This may be a problem when the size of the primes grows (in GAP it may need to grow as difficulty increases at a much faster rate than in RIC since the largest gap is expected to be O(log(p)^2) ).
edit: verification seems O(log(p)^5) instead of O(log(p)^4) as I originally wrote. They will eventually have problems with verification performance. This will affect pools too. Too bad... hope I'm wrong, I liked the concept.
edit2: as I read user Supercomputing wrote, GAP looks more gpu-friendly than XPM or RIC. Just pointing out this fact, this may be good or not, idk.
cheers!
Gatra