Hi bmurphy,
Memory foam and latex have a completely different feel and performance but the choice between them is an individual preference so the first thing I would do is test both memory foam and latex at local stores (that can provide you with the information you will need about what you are testing) so you can decide which of these two very different materials are your preference (see post #2 here).
I would never go by reviews when making a mattress choice because each person is very individual and what works well for one person (even if their specific body type and sleeping position is the same) can be completely unsuitable for the next person.
Post #2 here has more information about making comfort choices and the best way is with your personal testing and/or experience and if this isn’t possible then a more detailed phone discussion with the manufacturer (who knows more about their mattresses than anyone else and can give you some guidance based on the “averages” of their customers that may be similar to you) is the next best way to choose. Many manufacturers can also tell you about some local mattresses that are similar to one of their models so you can test a mattress locally to get a sense of what some of their mattresses may feel like. It’s also a good idea if you are unsure to make sure you know the details of any exchange or return policy in case you make a choice that is less than ideal.
Phoenix