I have several knives from both makers, including Leeks and the full sized Grip (do not own the mini). They are a bit different in style and design, a lot would depend on how you plan to use it. IMO, the Grip is going to be a more capable knife overall than the Leek, easier to hold and grip, better ergos.The Axis lock is one of the best; haven't had lock failures on the Leek, frame locks are generally considered reliable. The blade tip on the Leek is a bit fragile, had one damaged but Kershaw replaced it no questions asked. I like the Leek, but do find some models to be a bit more difficult to grip. Leek models I'd lean towards include the G-10 S30v (personal favorite, sees regular use on fishing trips); the g-10 is easier to handle, slightly wider and a bit lighter, and the g-10 is very grippy. The CPM D2 Composite blade and the S30v Random would be worth a look as well. Warranties from both company's are outstanding. In the Mini Grip I'd go for the D2, though the other blade steels are fine under most usage. Get one of each, both are relatively inexpensive.
For a bit more $$, you might consider the BM707; have one and like it. Very similar blade profile to the Grip (would be interesting to see a few pics of them side by side) scales are thinner and it carries great.