personally, it doesn't matter becoz
a) they stay on the mat for the upcoming few months only. once they grow and start to crawl, they will not stay there anymore.
b) mat are very easy to destroyed and change it frenquently. for my older daughter, we have already changed 4 mats in between.
since they crawl on it every day now, make sure you clean it frequent enough.
i think it really depend on the material of your floor.
如果是木地板, 買一捲過的地墊便OK, 去深水"土步" 買會便宜一點, 不然花園街都OK便宜.
我係一直放出來, 洗地掃地先收起.
但是好像洗地水抹不太OK, 表面那層會起.
(我習慣拖地前先拖它, 收起再拖地)