You live in China, so I can definitely see where you're coming from. But for someone just visiting temporarily, it's not like an extra US$8 for a trip that likely costs US$3000+ is going to break the bank.

I only use gmail and use Google maps all the time when driving.So I need a VPN. My VPN has never failed me and, while driving, I get precise and timely turn-by-turn vocal instructions with no interruption.
Some days, certain servers work better than others and you need to update your VPN list of servers regularly. Pretty simple.

"As noted above, Beijing can be challenging at times, but we're not talking about a 20 minute wait to connect."

Not waiting to connect, but I've certainly spent that amount of time in frustration trying to find a server and method that enables me to connect.

Okay. I will readily admit that casual visitors to Beijing are in for a steep learning curve with respect to VPN stuff. But, I have optimized my routine over the course of the past 5 years, and am happy to share with all who are interested. Even if I didn't have a Google phone, I would still be useless without Google (baidu and Bing simply don't hold a candle to Google), though Baidu maps are an exception, assuming you can read Chinese.

I have been using a Nexus 5x from Google (Project Fi) on my trips to China for the last six months. Google Maps and Gmail both work fine without a VPN in Beijing, Chengdu, Shenzhen and Guangzhou (the cities I have visited in the last six months). I was just reading my Gmail on my phone in the Beijing airport this morning.

For my laptop I have been using Express VPN and it works well.

I haven't been using Google maps in China, but Gmail has not worked for me for about 20 months now without a VPN. Were you roaming data?

Well, yes and no. I had data roaming enabled on the phone but with Project Fi you pay a flat $10/GB in the 120 countries that Google supports.

Gmail works fine without a VPN if you use a third party mail client (e.g. Apple), btw. You lose a lot of the gmail features, but can still receive/reply to all of your mail.

So your phone use roaming in every country, e.g. you will not have a chinese ip when you are online in china. Thats why it work for you.

But back to topic. Which Offline Map App is recommend in china mainland? Google Maps is blocked without VPN and offline maps aren't possible in china, Baidu is not in English and these Openstreetmap Apps aren't accurate to find anything. Any good Map Apps for foreigner to use in china mainland?

Deleted. I remembered that the Google maps offline hack isn't especially easy.

No need for a easy solution ;)
There was a App called Brut Google Maps, but it's to old now. Any replacement I don't know?

I'll post here if/when I figure it out. In the meantime, I highly recommend that you download cities/provinces you need from baidu, even if your Chinese reading ability isn't stellar, because their maps are detailed and useful. I actually didn't realize how much better they were than Google until recently. Google still doesn't recognize our newer subway lines here, and is really poor wrt banks, convenience stores, restaurants, etc.

I have a college friend who works for Google, on the Maps team of all places. I've complained to him numerous times about various issues:

1. The map/satellite view offsets that Google obviously has the software to convert coordinates for, because the problem doesn't exist on http://ditu.google.cn/

2. A lot of businesses don't actually show up. Some show up only when you type the Chinese name but not the pinyin/English name. An example is Charme restaurant in the Super Brand Mall. English name? Nope. But type in 港丽餐厅 and it'll at least find the place. I once booked a hotel thinking my company's office was in one spot, when in fact it was on the other side of the river about 12 km from where I thought it was. My friend got an earful for that one.

3. Landmarks, like Shanghai Disneyland, do not even show up when you search for them (since fixed; did NOT work when I was there a couple months ago)

4. Can't trust routings because new subway lines aren't in the map. It still does not understand that line 11 extends all the way to Disney.

I've told them numerous times that this is NOT acceptable and needs to be fixed. Google's got more money than God and I've got to think that it would have been fixed yesterday if they really cared, but they don't seem to care that they have a half-baked solution here.

That said, I still absolutely refuse to use Baidu Maps. So long as they keep blocking Google to try to force people to use Baidu, I won't use anything Baidu. Perhaps someone in China should read Aesop's fable about the North Wind and the Sun: once they let both companies compete on their own merits and let me turn off my VPN, I might give Baidu a try. Until then, they are playing the role of the North Wind and the harder they make it to use Google and screw around with my VPN connections, the more determined I am to use them.

1. Google doesn't have a great deal of incentive to keep its China maps current

2. Boycotting the superior product, out of spite, is childish

If they are so superior and the only service for everyone, why they don't offer a english interface? Even QQ have a international app.