Which American ally is rising to meet the challenge best?

Quick question.

Which American ally is rising to meet the challenge of a volatile future the best?

Don't play sea lawyer with me.  This is a basic question.  I'm talking militarily across the spectrum of land, air and sea.  I'm willing to take a look at changes in force structure, procurement and other factors.

What I'm not interested in is pure defense budget because that can be bastardized.  I don't care about retiree pay, VAT taxes, foreign aid that masquerades as defense spending etc...

I'm talking about running down the roster of nations that are allied with the US and determining who is doing it best and who is sizing up to be a credible ally when things go hot.

My list is simple.  I'm looking at procurement, forces structure and  how much they've attempted to embed themselves with our forces.  In this case flying off each others ships doesn't impress me.  I'm talking about exercises that challenge.  Going to each others leadership schools.  Attending tactical/strategic courses that hone skills.

My top 5 goes like this....

1.  Australia.

2.  United Kingdom.

3.  Japan.

4.  The Netherlands.

5.  S. Korea.

Rationale is simple.  Australia is going gang busters.  They have a plan for modernization across the force.  Intel sharing is outstanding.  Relations between forces is top tier.  Exchanges happen on all levels and exercises are conducted on a regular basis.

The UK comes in 2nd place because while their Air Force is at least keeping pace with a rapidly changing world, their Navy looks to quickly regain its place of prominence as the most lethal in Europe, their Army is lacking.  Additionally the Brexit mess is making future modernization iffy.  Nevertheless by my estimation they will continue the effort to be a major sea power which makes them undeniably valuable and as long as the 16th Air Assault and Special Ops units remain elite (along with the Gurkhas) they will provide outstanding specialized infantry to augment any effort.

Japan takes 3rd.  They are pushing along with some truly impressive programs. They've embarked on a stealth program, they're building an AESA equipped air to air missile, they have introduced new armored vehicles and they're even working on an advanced amphibious assault rig. Their Navy is looking shake the shackles from WW2 and develop a carrier force and they have recently developed a Marine Corps.  What kept them from claiming the number 2 spot is the total and complete focus on China.  Outside of pushing back against that threat they're more than likely to remain on the sidelines.

I won't expand on this list any further (perhaps in comment...I'm bushed) but that's how I see things.

I'm sure you guys will disagree but don't just tell me I'm an idiot, tell me why I'm wrong AND WHAT YOUR LIST IS!