Shurflo would be the most popular.
But I've never used one.
I've always bought the Chinese cheap ones off eBay. 5.5lpm for about 15 quid a go.
They draw less current than a shurflo.
They don't last all that long, however I do run them flat out without a controller so they do get some stick.
Still it's pot luck I've had one last a couple of years and some last a matter of months.
The problem with these pumps on ebay is not so much the pumping mechanism failing as the microswitch in the pressure switch. They burn out more quickly than on the big pumps and they burn out quicker if you don't you a controller with a CAL feature.
The reason is in part due to the high cut-off pressure they are set at. Some are set to 131psi which in my experience is way too high and completely unnecessary. The higher they are set, the higher the current being drawn at the point at which they cut off. So when the microswitch is operated there is considerable arching going over the contacts which causes them to burn out.
The object of the CAL feature on controllers is that you set it to shut off the pump as the current in the electrical circuit rises to a preset level due to pressure builing in the system when you shut the water flow off. So the mechanical pressure switch in the pump will probably never operate and so never burn out.
However, if you don't use a controller or use one without the CAL feature like I do, then try wiring a 40amp automotive relay into your system to take the load off the microswitch on the pump and you'll find these pumps will last a lot longer.
I was going through them at a rate of about one every 2-3 months before I did this on my trolley. Just to put this in perspective, I use a trolley all day 3-4 days a week on a very compact residential round so the pump gets subjected to a lot of cycling.
The good thing about these pumps though is their light weight when mounted on a trolley. They also don't require as big a battery so you save weight there also.