Rollups have become popular layer two networks for general purpose layer one blockchains that support smart contracts. In this work, we explore so-called based rollups: rollups which use the layer one network for sequencing. First, we explicate the benefits and potential pitfalls of this approach over centralized sequencers. Second, we use the Taiko rollup as a case study of early based rollups. In this case study, we analyze the cost and performance of Taiko and compare the findings to a similar-but-centralized rollup. Finally, we evaluate whether or not the purported properties of based sequencing are apparent in early systems based on the data collected in our case study. We find that while based rollups have promising properties, additional work is needed to make them competitive with centralized sequencers.