Caffeine - A Lift to Lift?

So, is caffeine the good guy or the bad guy? 
Yet again, there is a minefield of conflicting information regarding caffeine's benefits and dangers. However, recent studies are showing that caffeine can have beneficial properties while exercising and dieting. 
We all know that one too many cups of coffee can leave us hyped up and jittery, but can those very side effects assist us in our workouts? 
New research says it can actually help us perform better as the caffeine in coffee makes exercise feel easier, improves attention and reduces symptoms of fatigue. Indeed, ingested at the right time it can help us to exercise harder and for longer.
Studies show the optimum amount is 3-4mg of caffeine per kilogram of bodyweight one hour prior to exercise. 
With an average mug of instant coffee containing approximately 100mg of caffeine, this would mean that someone who weighs 61kg would need to consume 3.5mgs of caffeine; roughly equal to two large mugs depending on the strength of the coffee. 
According to a new report from the British Coffee Association, it has been noted that caffeine enables gym uses to perform for 30% longer, while improving alertness and the ability to sustain motor skills and aids persistence, vigour and output levels. 

Indeed, these studies have shown how caffeine improves endurance and performance in cycling high intensity running, repeated sprinting and sports such as football and rugby; some athletes have stated that they consume caffeine to enhance their endurance, alertness and motor skills.
Nevertheless, nutrition experts are still eager to point out the downsides to imbibing too much caffeine. Whlie the short term effects of caffeine on fatigue, endurance and performance are beneficial, there are many negative effects of caffeine including insomnia, anxiety, headaches, palpitations and high blood pressure. Further, high caffeine consumption can also cause high levels of homocysteine in the blood, raised levels of which are associated with strokes, heart-attacks, dementia and infertility.  
It would appear that caffeine consumption at the right time really can aid one's workout, although it be should enjoyed in moderation. 
It seems that once again, we really can have too much of a good thing. Moderation is the key.