Similar to Daveoc33.
I am new to this so started with day hire or borrowing a mates back up gun. Really wanted a MP5 because SAS, Die Hard, The Matrix....... Yes I am of that generation.
I bought my own Cyma Platinum MP5K which was epic compared to what I had been using. One of the guys at my local site had the Bolster armouries patch and a MP5K which looked very similar to mine so I asked him about it. He very kindly let me have a go on the range, I think he was curious as well.
The Bolster tuned variant was just better, smoother, more accurate, better sounding, snappy trigger response. Was it 2.5x as good as the platinum, difficult to say it did convince me to send mine off to be 'tuned' with a longer 'polished' inner barrel, high speed brushless motor, Gate Aster, hop up etc etc so it did make an impression. I am thankful I got to have a go as it showed me what I wanted and what could be done and how much better a well set up, shimmed and polished gun could be and stopped me going to a tech and just saying 'make it better' like the noob I am.
Out of the box they are expensive but they have got some lovely internal upgrades but it is the law of demising returns at some point.