My go-to rifle is an A-Bolt in .280 Rem (first version) I've had since 1993. I like removeable mags, because I like the ease and convenience of loading and even more, ease of unloading. And I have never once lost a removeable mag, so I don't see that as an issue.
That said, I'm so used to the much-maligned Browning floorplate/mag combo that I actually like it. I've also found my A-Bolt to be more accurate than I can shoot. Except for ONE load, (Rem 150 PSPCL), which shot about 1.5 MOA (5 shots), every factory load or handload shoots to MOA, and I have shot groups half that size and less. I assume the X-Bolt is equally accurate. And it keeps the 60-degree bolt lift, which I love; tons of clearance between hand and scope even wearing winter gloves. And I find tang safeties most instinctive to operate.
I always thought of the A-Bolt as a rather homely stock design, and I find the felt recoil a bit more than the same chambering in, say, a Rem 700. I have heard the X-Bolt is a more comfortable fit for people; I had a couple up to the shoulder and they felt quite nice. I do think the X-Bolt is one of the ugliest rifles to come down the pike in some time, but looks aren't everything. I personally think the Tikka T3 is a homely rifle as well, but it's sold like hotcakes.