Interesting. I have the Liquid 4pre which is going back to Focusrite for the second time in a year for a noisy channel. It will be sold as soon as it is fixed. As a mobile recorder, reliability is a priority. The owner of recording-microphones.co.uk lives on my street and he had an ISA 428 that died on him on a mobile session.
In the meantime, I found myself looking for 4 great channels to replace it. The Liquid was good - flat for a clean sound, choose a preset for a warm sound. I was going to miss it. And then I bought the Lake People C360 from Thomman a couple of weeks ago. A German company that supplies predominantly the German broadcast industry, but also seems to have a good reputation worldwide for headphone preamps
The Lake People is better than the Liquid 4pre in its 'flat' model setting. It is actually flatter and has less hiss at 66db. The Focusrite gets really hot, which I suspect has something to do with channels breaking. The Lake People gives off hardly any heat, so I can now rack with confidence. The switches all feel higher quality too. This is the best value for money I have found anywhere so far for a clean sounding preamp. It is also tiny, at a third of 1U. So now I am still 2 channels short and am circling around buying 2 Warm preamps. I have just speculatively bought a Joemeek MQ3 and borrowed a Warm from John at Recording Microphones. I hope the Joemeek will be better (or nearly as good), as they can be found for as little as £50, but I am not confident about it.
Update: the Warm is better than both! Seems to have valve punch and smoothness.