I can't enumerate all diffences but I'm mostly use C# (using DNN Source and compile our systems) and had some (severe) troubles with both versions. When you can decide what version is used then update to 4.5.3. I'm quite satisfied now with 4.5.3.

Actually I had no option - we produced a customized solution with four modules and started with 4.4.0. During the development we learned(and with discussions over the forum) that has bugs and some features depended on our modules. So I patched/fixed the development DNN environment (~ 100 lines) and it was no problem whilst I coded the modules but I knew I can't do this on the production release (regarding support & future versions). When the 4.5.0 was published I was eager to solve the problem (present the customer a beta version on the production server) but the update in the beginníng completely failed. After two days however the problems were manually fixed. I had a running development DNN 4.5.0 but I couldn't publish a production release (was not really critcal because the modules were not complete). The same with other problems did not automatically update from 4.5.0 to 4.5.1. Maybe you remember the 4.5.2 had a severe security leak so after three days of its pulication date the 4.5.3 was released.
And now the quintessence of the long story the attempts to produce a commercial release (4.5.0 + 4.5.1) took us together about a whole work - the update from DNN 4.5.3 took me 7 minutes and was to a large extend free of error and the compiled system with our modules ran / is running without problems.
I think we had no failures with our code (actually we changed nothing regarding the 4.5.3 release) so it must have had to do something with the update procedures. Maybe you should consider an update to DNN 4.5.3 as a 'better and quicker' solution.

good luck!