I have come from Infiniti I30, I35 then 04 TL and 06 TL to a TCH and while I do miss aspects of my TL I was ready to give up the performance becasue I was tired of $46 fill ups every 5-6 days. Going from a TSX you will miss the handling and performance, but if you can look past that I think you'll be happy. Going to a HCH will be a big step, going to a TCH will be a smaller step. I have driven a TSX, but my observations are more TL based:

TL had more supportive seats, compared toa TSX the TCH you will feel like you are swimming in the seats. The HCH will be a closer seat to what you are used to.

Sound system in TCH is awesome and is better than the 5.1 DVD-A in the TL. The HCH has a meager 160W system.

The HCH will handle closer to your TSX, but the performance will be meek. The TCH is a tad sluggish off the line, but when the ICE and EV are working together you have close to V6 performance. The TCH is soft and tends to lean in turns more, but is a nice luxurious ride. The TL was an awesome machine that I never thought twice if the car would hanlde what I would through at it. The TCH is ok, but you will not be doing any sport driving.

Acura/Honda year one cars are not the best with fit and finish, my 04 TL was a squeak and rattle bucket. My 06 TL was tight and quiet. I find the TCH to be a little loose feeling in the fit and finish department. I think the HCH will feel tighter, but as the current Civic is a year one car I suspect it is likely to have issues as well. The current TCHs are coming from Japan, Civics from Canada, you do the math on country or origin Quality. The biggest common complaint ont he TCH seems to be a center console squeak. I have had that and some back deck vibrations, both of which I have fixed myself.

The TCH has plenty of room is a fince car, the Civic will feel like a less expensive car and is tighter than your TSX inside. The TCH in my opinion has better styling and lines.

TCH did 5 stars in all crash test and excellent in IIHS tests except for whiplash. I beleive the Civic was close but did only 4 stars.

I was an agressive driver in my TL, I loved driving fast and hard. I have quickly adjusted to being a more relaxed and passive driver in the TCH, and actually less stressed with driving. I miss my TL, but am glad I have the TCH. The only TCH regret I have is getting port leather, it sucks, would prefer the near-Lexus level Toyota factory leather. Also wish I could have gotten a TCH with NAV, although from what I have seen and heard the Honda NAV is far superior to the Toyota NAV.

The TCH dash lights are lame, too bright at night and if you adjust them for night then they are too dim during the day. The TL had a great setup, when lights were off dash was MAX, when lights were on they were where you dimmed them, or coudl hit a MAX button to bring them to MAX, hit it again and they were back to dim.

Toyota ergonomics are a little confusing, inside door pull seems to be in a bad spot. Civic/Honda ergonomics are better, but if you have long legs like me, then the brake handle in the HCH will dig into your knee or leg.

TCH has huge glove box and center console for storage, HCH much smaller.

Rear legroom in TCH is large, HCH will be as tight or tighter than your TSX.

HCH will get better mileage than a TCH, but not by much, and surely once you consider the huge size and weight difference the TCH seems to be a great deal. My TL got 21-22 MPG using premium, my TCH is getting upwards of 35-36 lately using regular.