We were getting 2 guinea pigs for our son and daughter.  After much research we decided that the Habitat Plus was  going to give our new pets the mist spacious environment to grow and have fun.  
 Advantages:  1 habitat is sufficient for 2 baby guineas to play together.  We often join the 2 habitats together and they are able to have even more room to run.
Cautions-  The habitats are big and therefore you must have a space large enough to accommodate it adequately.
If you have the space, we highly recommend the Guinea Pig Habitat Plus for happy healthy Guineas