La Venta was first explored in the 1920s and then excavated beginning in the 1940s. A lot of the major finds from the site were moved to Villahermosa in the 1950s when archaeologists were concerned about their safety. Their motives were good but a lot of the pieces were moved without being marked.
Still, the museum is nice. It's in a jungly setting to try to recreate at least a little the feel of the original site and the signs are good. Definitely worth a visit, although it would have been better to go to the actual site.
We were there on a rainy day which made the photos not so great, but that's okay. This was the closest we came to visiting an Olmec site. Everything else we did was Mayan.