Recently I had a brief look into the datasheet of an attiny3226
It seems the tiny's are growing up now. It is a bit low on timers but got two uart (with SPI?) peripherals, and some extra things such LUT tables and pins can be mapped to another location, so you can have both an 8-bit port and uart running at the same time.
It has 32kB flash. There are also 4, 8, and 16k versions, but they cost the same so why bother? They are all below EUR1.5 and that makes price irrelevant for all practical hobby purposes. The are around 1/3 the cost of the atmega328, but the annoyance is that you need yet another programmer to get started.
There are also 14 pin and 24 pin versions, the 24 pin has a fine pitch package, which makes it less suitable for hobby, while the 14 & 20 pin packages are available in 1.27mm pitch, which even fits reasonably on perf board if you bend a few pins a bit. The 2.5mm length difference is also insignificant, so I'd go for the 20 pin variant. SOIC is small enough that size would hardly matter at all, and big enough for easy soldering / inspection / modifications / tinkering / etc.
But more importantly. I don't choose microcontrollers on a project basis. I want to buy some stock so I can just grab an uC when want to do a project. At the moment I have atmega8 and atmega328 on stock (and a bunch of STM32Fxxxx). And I never liked their pinout. You can't have uart and an 8-bit port at the same time and that is a nuisance for me.
A very important selection for me is if it is compatible with GCC. Does MSP430 do GCC? also have a few Cypress C7CY68013A chips, but these are a bit weird beasts. There is no flash to wear out
but they do need some other connection to get started. Normally they get their software (or should it still be called firmware?) over USB via DFU. But I never used them for anything different then a Logic Analyzer for Sigrok / Pulseview.