I've owned four Mooneys; C, [turbo] F, K & M models and have flight time in C, E, F, G, J, K, M & R model Mooneys. Additionally I have owned three Beech products and am about to get my fourth next month (S35 Bonanza and two B55 Barons so far). While it won't be popular on MooneySpace, I believe the 33/35 model Bonanzas to be the finest single engine airplanes made. If you want to hear others echo that sentiment, head on over to BeechTalk
Yes, the Mooneys are generally more efficient and cheaper to maintain but the Bonanza is just so much more comfortable and an absolute joy to fly. Cabin widths are virtually identical. You can even measure to the armrest cutout in a Mooney and show the Mooney is wider but that's inconsequential. The cabin is much higher in a Bonanza and the huge windows make it seem to be very much larger inside the Bonanza than the Mooney. Early Mooneys sometimes feel like I'm in a tank looking out the tiny windows.
Gross weights, useful loads and true airspeeds are generally greater for the Bonanza. That comes at a cost of fuel consumption and a bit more engine maintenance. For the same hull value, insurance and airframe maintenance will be very similar.
You have to look very closely at one or two things with a Bonanza. The first is the empty CG. Bonanzas do shift CG rearward as fuel burns off but it isn't nearly the issue that some make it out to be. My rule is I will not look at a 33/35 series Bonanza with an empty CG above 80.0. The second is specific to the 35 series Bonanzas. Make sure the ruddervators are in good shape. Replacements are available but they are quite expensive.
Download the free Bonanza Performance App and play around with various configurations for W&B. https://apps.apple.com/us/app/bonanza-performance/id910038344
Personally, I wouldn't look earlier than a J model Bonanza and only if it had an upgraded engine. You can put a -550 in a J or later Bonanza which transforms the airplane. At least get an IO-470 with a modern prop on any Bonanza.
Bottom line: They are both good airplanes with somewhat different strengths and weaknesses and they will appeal to a sightly different audience. You won't get a fair comparison here on MooneySpace. You also won't get a fair comparison on BeechTalk but ask questions on both sites and digest the information provided and see what's right for you.