Closing Recommendation
Pick your machine by the work you do most days. The Ajax Argo 2500 has more power, climbs slopes well, and gives careful weighing for the right mix, so it suits hilly or sloped ground and jobs where the mix must be exact; being a common machine, its service, parts, and trained drivers are also easy to find near you, and it sells fast later. The Universal SLM 2 has a bigger drum and turns well in tight spots, so it mixes more in one round and suits large pours on flat, open sites where you want fewer trips. So match the machine to your work: the Ajax Argo 2500 for sloped ground and exact mixing, the Universal SLM 2 for large pours on flat, open sites.