FWIW, I prefer TMX-100 over Delta.
The finest grain in a pictorial film is to be had with TMax-100 developed in Microdol-X (sadly no longer made, but Photographers' Formulary and Ilford make work-alikes [which I haven't tried, having a large stock of M-X...).
I also like the idea of shooting wide open in the sunlight - I shoot Tech-Pan at f2.0 and 1/1000 for my version of 'Sunny-11' (we never get an f/16'th worth of sun in Cleveland). A medium-yellow or yellow-green filter will give a 1 stop decrease in film speed if you want to shoot TMX at ASA 50; the filter will also give better tone rendition.
My experience is that TMX has about the same tolerance for overexposure as color negative film - you could probably expose it at ASA 12 and get printable negatives (that's printable, as opposed to optimum).
TMX's huge tolerance to overexposure means it has no shoulder to speak of. This means that highlight density just goes up and up - and beyond the range of the paper when it comes time to make a print. The naive interpretation is that the film blocks highlights - but the truth is otherwise, the highlight detail isn't blocked but may require burning in. The resulting prints have lovely highlight detail but take a bit more work to make.
Films with a shoulder compress the highlights. This means the negatives are easier to print and need less highlight burning. But it also means that the highlight detail you can get is all compressed. The shoulder in traditional films like Tri-X is the reason for the old split-grade adage to burn highlights with a #5 filter - the reason being an attempt to recover some of the compressed highlight detail. With TMax films there is no need to burn with a #5 as the detail isn't compressed.
TMax films change contrast with over or under development much more quickly than traditional films. Following Kodak's directions isn't hard, though, and a 15 second variation won't make any difference that you can see. The only place this sensitivity comes into play is when developing for N- or N+ contrast when playing around with the Zone system - the development change for a one-zone contrast shift is about 10% as opposed to 15% for old-technology films. The same sensitivity holds with temperature, but a $9 digital cooking thermometer from Target will provide all the accuracy one could ever need for measuring developer temperature.