The Blues have already beaten Edinburgh, the Dragons, Treviso and Connacht so far this term, while the Scarlets have picked up wins over Connacht, Aironi and the Dragons in their five league games to date.
Reigning Magners League Champions the Ospreys have won also won three times in five matches as they look to build on their record-breaking hat-trick of Celtic League titles.
And those three sides also remain fighting in Europe after securing home wins over Edinburgh, Perpignan and London Irish respectively over the opening fortnight of Heineken Cup action.
Only the Dragons have so far struggled with only one win in seven competitive matches.
And Jenkins, who is currently getting ready for the autumn Tests against Australia, South Africa, Fiji and New Zealand, is convinced that regional rugby in Wales is on an upward curve.
"The Dragons will be disappointed by their own standards but otherwise the regions will be reasonably happy," said Jenkins.
"The Scarlets have done really well, we all know what the Blues are capable of and then also the Ospreys.
"Apart from the Dragons they've all won their home Heineken Cup games."
But it is the Scarlets who have impressed Jenkins the most. The West Walians struggled last year, finishing ninth in the Magners League, but they have been a revolution this year playing some scintillating rugby.
"The Scarlets are on a learning curve and have young players," continued Jenkins.
"But this year there have been big improvements. They will be happy overall but disappointed with last week's loss to Leicester.
"They know they have work to do but they have certainly improved no end."
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