I'm thinking about this too! Switching - I keep longingly looking at CTC for next year and *sigh* I keep trying to get us through the stuff we are doing now. We have a 4th grader (9yr), a Kinder (5yr), and K-tag-along (almost 4yr - she just can't stand to be left out) and a 1.5yr old. We started homeschooling 2years ago (pulled the then 2nd grader out of private school we could no longer afford) and started with Abeka Academy. It was wonderful as it was a great 'transition' year for us. I learned her learning style, got comfortable with the idea of teaching her myself, and learned that we HATED pure workbooks
We still use Abeka for language arts and math at K....the programs are strong, but that was it. We needed something more alive for our history and science and music, and, well, everything else We did all sorts of research and thought that MFW would be the way to go - we bought MFW K and ECC. But the repetition took all the joy out of the schooling for my K-er. He nearly cried when we talked school time. We switched in January to Sonlight A after seeing how he was such a reader - he could read (or be read to) for hours! It has been an the BEST switch for him! He actually enjoys school again. He actually read for the first time yesterday! Woohoo!
Now I struggle with my 4th - we've been hanging in there with ECC. December was our low point - neither one of us wanted to do school
We were tired of repetition, and we found much of the suggested books dry. Text-like sometimes - what we had hoped to skip out on from Abeka. Abeka 4 Math was also causing tears. And we were dragging our feet so badly, we NEVER got to do art (her favorite subject). We were schooling from 8am to suppertime (like 5pm, sometimes later!) and still not getting through everything. I can't say she was lazy - just uninterested. So, we started adding in the read alouds from Sonlight's Cores F (Eastern - we are studying China, Africa, Japan, Saudi Arabia, etc) that I thought weren't too heavy (she's pretty mature). We also switched to Teaching Textbooks. That has made her like school again, and we can get through a day's work in a day, but now all she wants to do is read And it's hard to 'connect-the-dots' on most days for her. It's not that the curriculum is wrong, it just isn't what I think is best. There are still days she drags her feet...and she's really unhappy with the science. We love AIG, but Principles of Ecology is just dry 
We've enjoyed learning about other cultures, learning animals and ecosystems, and the like...but we are still dragging. And she loves history and art. Both which were feeling the lack of this year (history isn't really added b/c geo is the focus and we don't normally get to art b/c of dragging). We tried a reader from PHFHG (Who is MArco Polo) while studying China and it was her favorite read-aloud of them all!We KNOW that we want to start a history cycle next year. We were looking at the different cycles next year and we are almost positive that we will be starting CTC in Fall. She's excited about the art and the notebooking (we were lapbooking - but the repetition drained here there too - no longer fun). And she loves the graphics on the samples.
Oh, i want to switch now
Guilt over the $ is holding me back. So is the idea that maybe I'm wrong and the switch won't help - I know that the change of curriculum isn't a panacea. Arggghhh....And I haven't seen the whole thing in person, i just keep pouring over the samples on-line and the HOD catalogue. She's doing the same and has looked at other sites and can't see anything she likes better either. Is it worth it to switch mid-year? Can we stretch CTC into a year and a half? I know there are things she's going to have to learn (narration) and work on getting better (dictation). But the rest of the placement chart puts her squarely in the CTC bracket. I though about starting PHFHG for the end of this year, but couldn't see the economic advantage...but maybe that's an option too.
Thanks for reading all of this! Thanks for any advice - I'm confused and not sure where to go from here. I'm definitely in the 'newbie' group here - and I'm feeling it
*disclaimer - none of the above mentioned curriculum is "bad," just not for us apparently*
So, so, so many families make a switch midyear -I think you should join them.