I set up a 40 gallon mixed reef with no sump a little over a year ago. I did a lot of research on skimmers, and decided to not even use a skimmer on that tank. It has been running for about 14 months and everything does very well ( soft corals and LPS). A lot of people run smaller tanks without a skimmer. More water changes and strong surface agitation are important if you are not using a skimmer. This is just my experience, I hope it is helpful.
I like the Tunze comlines. I did a diy sump and made the skimmer section smaller. Runnin a aquamaxx ws-1 in it now but thinking about the comline if I swap it out because it shares a small footprint that'll fit in that chamber and I think those tunze are slightly over built (a good thing) being ozone ready, etc. (I'd have to double check this) and I run other tunze products that are well built an run reliably