Its really easy to bang out a spreadsheet to compare DMS to RMS to CTI to Loki assuming all things being equal. They never are equal and so you have to give weight to other items as well.
In 38mm and 54mm cost per flight, CTI break-even is nearly always first when comparing similar motors in the 6 to 10 flights range. RMS break-even is in the 8 to 22 flights range. Loki is 10 to 25 flights range. If you look at how much is costs per N-s per launch, CTI break even is 3 to 10 flights, RMS is 4 to 20 flights and Loki is 10 to 15 flights. (selected DMS H123W, RMS H100W, P38 H144W, Loki H144W; DMS J270W, RMS J350W, P38 J290W, Loki J528W; DMS J450DM (no white in that range), RMS J415W, P54 J760W and Loki J525W)
Most important thing is how easily you can get your motors. If you have an on-site vendor, support them and fly whatever they sell. If not, then you have to consider either shipping or doing a bulk buy at a regional launch and bring it home with you. Second is how often most rockets are unrecoverable at your sites. Talk to other flyers and see how often they lose cases. If its less than the break-even point, keep going with DMS but if losing a case is rare, it's better to invest in cases and go with reloadables because the long-term cost is lower and you have a much greater selection. Lastly, what other activities are you going to do with motors. If you want to stage or cluster, CTI is the absolute best with the pressed pellet in the top grain. If you want to get into research, the Loki snap rings are ideal. If all you want to do is 'whoosh....pop!" then you can't beat DMS for ease and quick turn around (but CTI is really close to those as well) If you want higher Length to Diameter ratio (the L to D I used showed up as a smiley) motors, no one can touch Loki, they have 38mm Ks and 54mm M motors. If you're in California, getting Loki motors involves jumping through some serious hoops so that may not even be an option.
Rocket science isn't just designing the rocket to be stable in flight, its also analyzing what motor to use and why. It's when to use electronics and which ones. There are lots of things in this hobby that involve work and research, motor vendor and type selection is just one and its different for every flyer.