I may be wrong about this but this is my view on the various LPSU units around and their costs and perhaps as well their abilities. Firstly Baldwin Audio seems to be a one man operation and Paul designs makes and sells his products himself . His costs and over heads are kept small and he can probably work on a much smaller profit margin . I can not be sure but I would say his LPSU are very strictly engineering based and do not include boutique or special components such as plastic film caps etc. What he uses are good quality and correctly specified parts that will work safely and correctly and meet the specifications you ask for . Special units with higher power such as 4amp 12V cost more and in my case just over £200 including postage . Same for the dual 5V supply .
Others like the Paul Hynes , Sbooster have specific design and possibly exotic components and they employ other people to produce them this will both increase costs and need a higher profit rate to pay wages etc so they will price accordingly . They may even sound or perform to a higher standard which I would not know.
What I would say about those I have favoured is that they are very solidly made , they look very professional they are properly 240V specified which is important 220v or 230v units which may well have just enough to cope Transformers in will be stressed when operated at 240 v all the time (I have a voltage screen on my connection box which shows my voltage is never less than 242V and often 250v) so I am pleased that what I am using will be comfortable working with this . I did notice an improvement in sound quality as each unit was added and that improvement has stayed . All of the other units I am sure will also work and be safe and may well give even better sound quality only you can decide if the additional cost involved is money well spent . I am happy with what I have currently and if I need any new LPSU i will be going back to Baldwin Audio .