I like the interface of Sideline better than Line2, though the banner ads on the bottom are quite prominent and probably not something you want to live with permanently.
Sideline also offers a few smart features that can automate some processes, like setting up auto-replies, selecting a new text tone, and setting up a do-not-disturb time so you can have your second number be off limits during leisure hours. The design is elegant and in keeping with Google’s aesthetic, and I found the app to be reliable and rapid.
There’s always Google Voice
If you like the cost level of free, then there’s always Google Voice to consider. The service goes back seven years; it came about in the days when business users who had to juggle an office line, home landline, personal mobile, and a work-issued BlackBerry.
Just like the other apps you get to pick a phone number, which you can use for free text messages and phone calls. International calls are relatively cheap, and it includes several nifty features: Google Voice calls can ring multiple numbers at once, screen your calls, and transcribe your voicemail messages (although sometimes they’re hilariously wrong).
To get the full list of features, however, you’ll need to use Google’s Hangouts app. That’s where SMS/MMS messages and the dialer live, which also integrates with your Google contacts. The app isn’t exactly a shining star in the Google lineup, but some recent updates have ramped up its stability and squashed the most annoying bugs.
The big question mark here is if Google Voice will stay a separate service or get swallowed by Project Fi. If you move to Google’s MVNO, you have to use your Google Voice number or surrender it forever. Voice hasn’t gained any major features in quite a while, so the future of Google’s support for the service is still a little murky.
Go dual SIM, if you can
There’s also another option that’s slowly gaining traction: dual-SIM phones. The primary benefit would be with international travel. You can still get messages from your primary SIM, but use a temporary local SIM for data since most carrier international plans are ridiculously overpriced. You may still be able to use your primary number for calls, however, if your carrier supports Wi-Fi calling.
However, it’s not a terribly popular method here in the U.S. right now. Probably the best dual-SIM Android phone you can get in the U.S. is the OnePlus 2. Most other dual-SIM phones are budget models that might not be all that appealing to use as your daily driver. And U.S. carriers are, at this time anyway, loathe to offer support for such phones, which would require granting you two separate numbers. However, if you want a temporary solution for an upcoming trip overseas then a two-SIM phone would be great to have.
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