Hi Lisa_mocha,
There is no “better or worse” between Talalay and Dunlop and the choice is strictly a matter of preference. You can read more about the different types of latex in this article and in post #6 here). There is also a little more about the differences in how they “feel” in post #7 here but feel is subjective and your own testing on both materials is really the only way to know for sure which one you prefer.
I would be very cautious about ordering a mattress that used a material that you hadn’t tested in person so you are at least somewhat familiar with the general “feel” of latex. Mattresses with latex in the top few inches of latex in the comfort layers can give you a good sense of what latex feels like in general terms but I would make sure that the latex is in the top layer of the mattress and that there are no thicker layers of polyfoam above it.
With latex allergies it would depend on the type of allergy (see post #2 here). If it is a contact allergy then the latex will be covered and there will be no contact so this type of allergy (acutually a sensitivity not a true allergy) is not usually an issue. Contact allergies are generally to the ingredients that are used to make thelatex foam not to the latex itself although it’s also possible that some of the surface proteins of natural latex could be involved (which are mostly washed out with latex foam).
If the latex allergy is a type 1 allergy (which is very rare and much more serious) … then I would avoid natural latex in any form or in any blend completely.
You are choosing between “good and good” although there are significant differences between all of your final choices in terms of design, materials, price, and options before and after your purchase (and some of the other online manufacturers or retailers that you haven’t included). Post #2 here can help you make final choices when you are down to final options where there are no clear “winners” between them except based on the criteria that are the most important part of your personal value equation.
I would also verify that all of these can ship to Canada and make sure you know the cost of shipping and any charges across the border (taxes and brokerage fees) which may also play a role in your choice.
Hopefully you’ve read post #1 here which also has a link to a list of the members here who sell latex mattresses online.
Phoenix