1. Isofrane
The daddy of them all, Isofrane: http://isofrane.com/
Amazing, hefty and comfortable- loads of reviews of thsi online. This is the one to compare all others to. Will not catch dust or lint etc. One drawback is price- expensive, particularly if you prefer rubber to leather etc.
2. Borealis
A pretty good alternative is the Borealis version- https://www.borealiswatch.com/
Borealis have a strap that is as comfortable as the isofrane, appears to be the same material etc. but a fraction of the price. The strap is very similar and also is slightly thinner, for me a bit better fit than the isofrane imo. The only drawback drawback is the branded buckle. However, if I was to choose between the two I would go for Borealis with a replacement buckle. A while back I received a Borealis rubber strap and same day put up an unworn isofrane strap up for sale. Borealis keepers are different to Iso- both rectangular.
3. LocalTime
There is a third alternative. Just in is a LocalTime rubber strap, very similar again to Borealis in thickness and design but a bit stiffer. No lint issues, and is less expensive. The buckle is good quality and sterile, better out of the box than Borealis. For larger watches the slightly stiffer rubber strap keeps the head in place a bit better, so i'd rate this the same as the borealis.
https://www.ebay.com/itm/Vintage-Style- ... 7518d1458a
LocalTime keepers are similar to Isofrane with one angled, one rectangular.
For bronze watches there are a few sources of replacement bronze isofrane buckles etc. so with either the Borealis or Localtime straps, you can end up with a bronze buckle 'isofrane' style high quality strap, at half the price.
There are others such as offerings from Maranez, would be interesting to get opinions on these also.
Here are a few side by side shots for Borealis (black) and LocalTime (green)
And of course the isofrane
