I own the Makita, a friend owns the Festool TS55R, I've used both quite a bit.
I know the issue the op is referring to, the guides on the saw base are further apart than on the Festool so as you get to the end of the track the first guide can leave the rail before you've finished the cut. However if you set the 1400 rail so it overhangs the sheet equal it will make the cut, two small marks on the rail helps to line it up correctly without having to measure each time.
Compared back to back both saws have their positives and negatives. The depth setting on the Festool is much better, especially on the newer TS55R. The blade change mechanism is slightly better too, the Festool locks it's blade whereas on the Makita you still have to manually lock the spindle, no big issue but worth pointing out. The Makita has a much better motor, more powerful and quieter than the Festool, the Festool is also quite fussy about its power supply, if you are using it on a long extension or other tools are running from the same power source the motor slows dramatically to the point it can struggle with 18mm MDF. This is made even worse when running through an extractor. The anti tilt mechanism and scoring function are positives on the Makita too, although if you are using as a system your Festool tools will not run on the Makita rail, the extra lip used for the anti tilt gets in the way. Used with an extractor there is no noticeable difference between the two.
The fact is both are very good, a plunge saw really is a very versatile tool and an absolute godsend if you regularly cut sheet materials. They also save a heap of time if you have to cut doors down, say after floor coverings have been fitted, they'll slice through prefinished veneered doors with virtually no splintering. The more you use them, the more things you find for them to do as well, well worth the purchase price over a regular circular saw in my opinion.