Re canard configuration, one other problem is "Deep Stall".
In the normal run of things, the fore-plane is designed to stall first, thus creating a pitch-down moment, reducing the main-plane AOA and stopping it from stalling at all. This is why Canards are sometimes claimed to be "Un-stallable".
If, however, an external influence (Severe Turbulence, wake or rotor for example) does force the main-plane past it's critical AOA, the resultant loss of lift causes a nose UP moment, exacerbating the stall.
This has been experienced in aircraft such as the Long-ezy and Cozy, and is unrecoverable.
That's a function of the specific design, not of the use of the canard or forward lifting surface.
The same may be said of some conventional designs for a variety of reasons. A LR35, for example, may be put into a deep stall which can become irrecoverable, or may take 12,000' or more to recover. The design, loading, use, and construction of the specific airplane are all critical to the issue. The lear may be flown to a place from which it cannot return. The solution? Don't fly it there. The experimental homebuilt airplane may have any number of unique features as a function of individual construction, and have further been released in plan form with differing airfoils, different modifications, etc. To suggest that the design itself is unrecoverable is in error, and far too simplistic.
With respect to flying in turbulence, the ability to ride out the bumps in comfort is a function of wing loading, like any aircraft. The Piaggio Avanti is a conventional airplane with a forward wing (Piaggio is loathe to call it a Canard because it isn't a control surface). It has about the same wing area as a Cessna 182 but weighs more, with a high enough wing loading it flies very well through turbulence. Depending on the CG, the horizontal stab can and does produce positive lift in that design. The Avanti is a conventional airplane with somewhat unconventional loading. It flies into and out of a stall quite beautifully, incidentally, exhibiting similiar characteristics to many "canard" aircraft...it sits at a high angle of attack with aileron control, buffeting with some rudder shake and rear vibration. It stays stable in that condition in a stable 2,000 fpm descent, with control authority available. It may be flown out with conventional technique by decreasing angle of attack, or may be flown out on power.
Other Canard aircraft I've flown such as the Long EZ, Cozy, etc, behave in a similiar manner. Certainly incidents have occured with some experimentals in which the aircraft became unrecoverable, and that may be a function of the angle of incidence of either wing, the airfoil, construction technique, loading, simply having flown beyond the design limits into an unrecoverable arena for that specific airplane, or other related or non-related factors. To suggest that it's a function of having a canard would be wrong.
Cases have occured in certain conventionally configured airplanes in which the airflow over the horizontal stab has been blanked or disburbed such that the surface was no longer capable of providing recovery, or the angle of attack reached such that the horizontal stab provides no response, or a negative response (or has been modified to produce such a result, such as tailplane icing). The same has occured with canard configured aircraft in which the forward wing disturbs or alters airflow over the main wing, producing similiar results. The general idea on the Canard is to make the forward wing stall first, but that can backfire, too. For a true canard, one providing pitch control, the "elevators" move backward to those found on a traditional tail-mounted horizontal stab. At high alpha or high AoA, the potential exists for a forward wing with a small elevator to respond to nose-up commands, but to lose authority in down commands as the elevator is deflected upward into the stalled region of the canard.
Variances in the actual construction of the airplane make a big difference. Most experimental canard configured airplanes are made of shaped foam, covered in fiberglass, Any variance in the foam or finish can produce differences in the airfoil, and every single difference varying from the design has an impact in some way. Additionally, some airfoil ventures such as the Glascow University airfoils produced unusual and unexpected results in the early years, such as significant loss of lift or pitching-down in the presence of contaminants such as raindrops. to further complicate that, many of the canard aircraft fly with airfoils that operate closer to laminar, experiencing airflow separation farther back on the airfoil than typical production airplanes. Any distrubance of the airflow causing separation also produces a correspondingly larger performance or handling penalty. In the past for some airfoils, this has included bugs, raindrops, nicked paint, etc...producing big performance losses. (I've seen 10-15 knot performance loss in some airplanes when entering visible moisture, for example, or changes in controls requiring repositioning the stick by 2" or more to compensate, upon entering visible moisture, or with a change as seemingly insignificant as a paint stripe).
There are numerous factors to consider, far beyond simple employment of a canard (or otherwise) when planning for performance or behavior.