Blue-faced:
Pros of the Manta: super simple, cheap, can replace the battery easily, small – can be used as a watch, have fancy color ;-)
DSAT-based algo computer, which is the less conservative, so difficult to bent for rec dive on air or 32% (unless indeed your forget to reset it for the second dive, as it will move to 50% mix, then you are for sure going to bent it)
Cons: doesn’t have second in gauge mode. I don’t think they do pink color.
Similar price range is the uwatec tec2G which many people are using
Cons: give you a little less bottom time when you dive it computer mode. Little more bulky that the manta. Cannot wear as a watch.
Pros: have second and average depth in gauge mode
What Lamont wrote is 200% true and I think many people went through this process: basically don’t worry too much about it. Computer diving is not that bad! And full transition to Timer when you fel ready.
I’ve been using the Manta (bought older model on sales for 200$) for a long time, and as my back up computer after I got the tec2g (<250$ on ebay – I’m cheap) and the manta in computer mode. It’s still convenient when doing multiple dives per days. With a 3mm wetsuit for vacations diving, it’s just so simple.
If you take fundamental, you can still borrow a BT from a buddy to get the seconds in gauge mode.