On Android, I use an email app called AquaMail. The free version handles only 2 accounts, while the paid version ($4.95) handles more. The interface is powerful and highly customizable, but very intuitive and easy to use. It's been rock-solid stable on all of my Android devices, and is probably the best Android mail app I've used. It handles POP, IMAP, Gmail, and Exchange accounts. I highly recommend this one!
https://play.google.com/store/apps/d...AquaMail&hl=en
I use a calendar app called aCalendar. I like the interface a lot better than the stock calendar apps on my Samsung and LG devices; it's smooth, sleek, and intuitive, and has daily, weekly, and monthly views accessible by simple swipe. It handles multiple calendar, or course, including Exchange and Google, and has a nice set of configuration options. I have only been using it for a few months, but so far, I really like it. The paid version is $4.95.
https://play.google.com/store/apps/d...calendar&hl=en
On my Windows PC I use Thunderbird as my email client. It natively handles POP, IMAP, and Gmail. I know it will handle Exchange accounts, but I believe it needs a plugin to do so. I never use it for my work email, which is my only Exchange account, only for my personal emails, which are all IMAP or Gmail. It was recently upgraded to include a calendar extension that accesses Google calendars and works very well, though again, I have not tried to connect it to an Exchange calendar so I don't know how well or poorly it might work. Still, it's worth downloading it and giving it a try on your laptop, it may fit the bill for you, and best of all, it's completely free.
Can't help you with the iPad, though. My only Apple device is an iPhone 3Gs, so I'm a little behind the times on that side of things.