I have a Sizzix Big Shot Plus die cutter that I absolutely love. I can use the AccuQuilt dies or Siizzix dies in my Sizzix. Both the initial Sizzix "machine" and dies are MUCH less expensive than the AccuQuilt versions, but work exactly the same way. (For example, a die to cut 2-1/2" strips is $40 for Sizzix compared to $80.45 for an Accuquilt die the last time I checked on Amazon.)
The dies do dull after 100's of cuts. I haven't tried to sharpen mine yet. As for the clear cutting pads/mats, I have never had a problem with one breaking or cracking and I've used them a LOT. I saw a YouTube video where someone substituted a regular cutting mat for the clear Sizzix mat/pad. I ordered a large self healing cutting mat from an online art supply source for $30 and my husband cut it into 4 mats sized for the Sizzix. They work just like the Sizzix mats, but are a lot cheaper. I really like my Sizzix Big Shot Plus - it saves me lots of time and the cuts are always perfect.